SERV1838 June 2007
GLOBAL SERVICE LEARNING TECHNICAL PRESENTATION
735 (B1N), 740 (B1P), AND 740 EJECTOR (B1R) ARTICULATED DUMP TRUCKS TIER III
Service Training Meeting Guide (STMG)
735 (B1N), 740 (B1P), AND 740 EJECTOR (B1R) ARTICULATED TRUCKS - TIER III AUDIENCE Level II - Service personnel who understands the principles of machine system operation, diagnostic equipment, and procedures for testing and adjusting.
CONTENT This presentation provides basic systems operation of the operator's station, engine, power train, hoist, and braking systems for the 735, 740, and 740 Ejector Tier III Emissions Articulated Trucks. OBJECTIVES After learning the information in this meeting guide, the technician will be able to: 1. locate and identify the major components in the operator's station, engine, power train, hoist, and braking systems; 2. explain the operation of the major components in the systems; and 3. trace the flow of oil through the systems. REFERENCES 725/730/735/740 Articulated Trucks- Electronic Control Systems ACERT™ Technology 700 Family Articulated Trucks Operating Tips Introduction to the 700 Family Articulated Trucks (Video) Cycle Counter/Operator Monitor for Cat Articulated Trucks Salesgram Automatic Lubrication System for Cat Articulated Trucks Salesgram
SERV2744 AERQ0002 AERV5895 AEVN5894 TEKQ0328 TELQ3831
PREREQUISITES "Fundamentals of Engines Self Study Course" "Fundamentals of Mobile Hydraulics Self Study Course" "Fundamentals of Power Trains Self Study Course" "Fundamentals of Electrical Systems Self Study Course" STMG546 "Graphic Fluid Power Symbols"
Estimated Time: 4 Hours Visuals: 182 Handouts: 26 Form: SERV1838 Date: 06/07 © 2007 Caterpillar Inc.
TEMV3001 TEMV3002 TEMV3003 TEMV3004 SESV1546
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TABLE OF CONTENTS INTRODUCTION ........................................................................................................................5 OPERATOR'S STATION..............................................................................................................6 Dash ........................................................................................................................................7 MACHINE ELECTRONIC CONTROL SYSTEM ...................................................................18 Messenger Display................................................................................................................19 Messenger Menu Screen.......................................................................................................21 Messenger Information Screens ...........................................................................................22 Messenger Main Menu .........................................................................................................23 Performance Menu................................................................................................................24 Performance Menu Options..................................................................................................25 Operator Menu......................................................................................................................27 Operator Menu Options ........................................................................................................28 Totals Menu ..........................................................................................................................30 Totals Menu Options.............................................................................................................31 Settings Menu .......................................................................................................................35 Settings Menu Options .........................................................................................................36 Service Menu ........................................................................................................................38 Service Menu Options ..........................................................................................................39 C15 ACERT™ ENGINE ............................................................................................................46 Engine Electrical Block Diagram .........................................................................................50 High Coolant Temperature Derate........................................................................................60 Intake Manifold Air Temperature Sensor Derate .................................................................62 Low Oil Pressure Derate.......................................................................................................65 Virtual Exhaust Temperature Derate ....................................................................................66 Air Inlet Restriction Derate ..................................................................................................69 Fuel System...........................................................................................................................70 Power Derate.........................................................................................................................71 Fuel Temperature Derate ......................................................................................................76 High Fuel Filter Restriction Derate ......................................................................................77 Engine Brake.........................................................................................................................81 COOLING FAN SYSTEM.........................................................................................................88 POWER TRAIN ........................................................................................................................94 735 Transmission Electronic Control System ....................................................................100 735 Transmission Hydraulic System ..................................................................................105 740 Transmission Electronic Control System ....................................................................120 740 Transmission Hydraulic System ..................................................................................126 Differential System .............................................................................................................148
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TABLE OF CONTENTS (continued) STEERING SYSTEM ..............................................................................................................161 Secondary Steering System ................................................................................................169 HOIST HYDRAULIC SYSTEM .............................................................................................172 Hoist Hydraulic System - Dump Body...............................................................................183 Hoist Hydraulic System - Ejector Body .............................................................................187 BRAKE SYSTEM ....................................................................................................................197 SUSPENSION SYSTEM .........................................................................................................209 Adjusting the Suspension Height........................................................................................211 CONCLUSION.........................................................................................................................213 VISUAL LIST ..........................................................................................................................214 HYDRAULIC SCHEMATIC COLOR CODE.........................................................................217 HANDOUTS.............................................................................................................................218
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735 (B1N), 740 (B1P), and 740 EJECTOR (B1R) ARTICULATED TRUCKS TIER III
© 2007 Caterpillar Inc.
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INTRODUCTION Shown is the right side view of a 740 Ejector Articulated Dump Truck. The 735 and 740 Articulated Dump Trucks have been redesigned to meet U.S. Environmental Protection Agency (EPA) Tier III Emissions Regulations for North America and Stage III European Emissions Regulations. Technical Specifications 735
740, 740 Ejector
Serial No. prefix
B1N
B1P, B1R
Engine Tier III Net Power (SAE J1349)
C15 ACERT™ 304 kW/408 Hp
C15 ACERT™ 340 kW/457 Hp
Transmission No. of Clutches
ECPC 8F/1R 6
ICM 7F/2R 7
Brakes
Hydraulic Brake
Hydraulic Brake
Hauling Capacity
36 tons
42 tons
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OPERATOR'S STATION Shown is a view of the 735/740 operator compartment. The operator seat (1) is centered in the cab with the trainer's seat (2) positioned to the left. The hoist control lever (3) is on the right console next to the transmission control lever (4). The 735/740 is equipped with a standard electronic instrument cluster (5) and a Messenger Monitoring System (not shown) is optional.
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Dash The dash switch (1) controls the head lights and tail lights. The dash switch (2) controls the rear work lamp. The dash switch (7) controls the rear windshield wiper. The dash switch (9) controls the hazard lights. The instrument cluster (3) displays the operating information of the machine. The dash switch (4) turns the cross axle differential on and off. Push the top half of dash switch (5) to activate the secondary steering motor. The switch is spring loaded. The switch will automatically return to the OFF position when the switch is released. This deactivates the secondary steering motor. Press the top of switch (6) to activate the air conditioning system. The cigarette lighter (8) can be used as a 24V power receptacle. This power receptacle can be used to power automotive electrical equipment or accessories. Remove the cigarette lighter before using the power receptacle for another purpose.
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The engine key start switch (10) is operated by a key. The engine start switch has three positions. The key can be installed or removed in the OFF position. The ON position will activate the electrical circuits in the cab. The START position will crank the engine. Turn the temperature control switch (11) clockwise or counterclockwise to adjust the air temperature within the cab. The rotary control fan switch (12) has the following five settings: - OFF - Low speed - Low medium speed - High medium speed - High speed
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The LED indicators will illuminate either red, green, amber, or blue to alert the operator that a certain condition exists in the represented machine system. Fourteen of the indicators are driven by the Transmission/Chassis ECM through the CAN Data Link. When the key start switch is first turned ON, the number that appears on the center display is the cluster part number. Cycle the key start switch 3 times ON/OFF within 10 seconds to enter the diagnostic mode. The LCD display in the center of the instrument cluster displays machine ground speed, actual gear, direction, and service hours. The LCD will also display diagnostic codes. The gauges on the left display the engine coolant temperature and the engine oil pressure. The gauges on the right display the torque converter oil temperature and the fuel level. Starting at the left of the New Cluster Display and working toward the right are the following indicators: Left Turn Signal - This indicator flashes green when the left turn signal is operating. The signal is a switch to the battery signal direct to the instrument cluster through terminal "10" on the instrument cluster connector.
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Machine Filter Warning - This indicator alerts the operator that service is required. A category 1 warning alerts the operator that the air filter is restricted, for example. The air filter requires immediate service. A category 2 event alerts the operator that the air filter is plugged. The air filter must be serviced to avoid black smoke and loss of engine power. A category 3 event alerts the operator that either the transmission filter or the output transfer gear filter is plugged. The plugged filter requires immediate service. Secondary Steering - Secondary steering is illuminated when there is a problem with the primary steering system. Stop the machine and do not operate the machine until the cause has been corrected. Primary Steering System - This indicator will illuminate red when the steering pressure switch is open indicating a loss of steering pressure. A category 3 event is logged and the alarm will sound if this warning occurs when the engine is running. A category 2 event is logged when the engine is not running and the indicator is active. Brake Oil Pressure - This indicator will illuminate red when the service brake accumulator oil pressure switch is open which indicates low service brake oil pressure. A category 3 event is logged and the alarm will sound if this warning occurs when the engine is running. A category 2 event is logged when the engine is not running and the indicator is active. Brake Temperature - This indicator is only used on the 735 and 740. The indicator will illuminate when either the front or rear brake coolant oil temperature is above 107° C (225° F) and this warning will reset when the temperature goes below 93° C (199° F). Transmission Hold - This indicator will illuminate amber when the transmission "Hold" feature is activated. Transmission Fault - This indicator will illuminate amber when the Transmission/Chassis ECM detects a transmission or power train diagnostic code or event. When more than one diagnostic code or event is active, the Transmission/Chassis ECM will send the highest active warning level to the instrument cluster. Also, this indicator will illuminate amber when the Output Transfer Gear (OTG) temperature becomes to high. Action Indicator - This indicator will illuminate amber when the Transmission/Chassis ECM detects faults in a machine system. Parking Brake Engaged - This indicator will illuminate red when the parking brake is engaged. A warning level 1 will be indicated when the parking brake is engaged if the engine is started and the shift lever is in the neutral position. A level 2S warning will be active if the engine is started and the parking brake is engaged when the shift lever is in a position other than neutral.
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Charging System - The Transmission/Chassis ECM monitors the alternator "R" terminal and the system voltage. The indicator will illuminate amber according to the following conditions: - When the key start switch is in the ON position and the engine is off, if the measured voltage is less than 22.0 V or greater than 31.0 V, a level 1 event will be indicated. - When the engine is running and the measured voltage is less than 22.0 V or greater than 31.0 V, a level 3 event will be indicated. - When the engine is running and the voltage measured is between 22.0 V and 23.8 V or if the engine is running and the measured voltage is between 28.5 V and 31.0 V, a level 1 event will be indicated. - When the engine is running and the measured frequency is less than 90 Hz, a level 1 event will be indicated. Machine Security - If equipped, the indicator will illuminate when the machine security system is activated and an attempt to start the machine is made. Differential Lock - This indicator will illuminate amber when either the inter-axle lock or the cross-axle lock is engaged. This warning is a level 1 event. High Beam - This indicator will illuminate blue when the high beam head lamps are ON. Retarder - This indicator will illuminate green when the Transmission/Chassis ECM sends a message to the Engine ECM to activate the engine retarder. Retarder Upshift/Drive Train Overspeed - This indicator will illuminate orange when the upshift warning levels (modified shift points) in the Transmission/Chassis ECM are reached and the engine retarder is active. The lockup clutch also disengages and the transmission upshifts. Hoist Control - This indicator will illuminate red when the dump body is in any mode other than "float." Right Turn Signal - This indicator flashes green when the right turn signal is operating. The signal is a switch to battery signal direct to the instrument cluster through terminal "11" on the instrument cluster connector. NOTE: Refer to "Handout No. 2" at the end of this presentation for a list of warning conditions and warning levels.
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The retarder control (1) is located to the right side of the steering column. The retarder control has the following four positions: - DISENGAGED - lever at the top position - MINIMUM - lever one click down from top position - MEDIUM - lever two clicks downward from top position - MAXIMUM - lever three clicks downward from top position If the accelerator control is activated and the retarder control is in the MINIMUM position, the MEDIUM position, or the MAXIMUM position, the retarder will engage when the accelerator control is released. The retarder will disengage when the accelerator control is pressed. NOTE: The retarder is factory set to operate automatically. Caterpillar Electronic Technician (Cat ET) may be used to switch off the automatic function of the retarder. If this function is switched off, the retarder can be manually engaged regardless of the position of the accelerator control.
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The retarder indicator will be illuminated (steady ON) when the engine retarder is enabled (low, medium, and high). In this illustration, the hoist control indicator (2) ("Not in Float") is illuminated. The center display shows the speed (3), gear (4), and service hours (5).
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The hoist control lever (1) is located on the right side of the operator seat. The hoist control has the following four positions on dump body trucks: LOWER position - Move the hoist control to the LOWER position to lower the body. Push the hoist control fully forward for maximum lowering speed. Reduce hand force on the hoist control to reduce the speed. Hold the hoist control forward until the body is approximately 600 mm (24 inches) above the rear frame. Release the hoist control. The hoist control will then return to the FLOAT position. The body will continue to lower under the effect of gravity until the body rests on the rear frame. FLOAT position - Move the hoist control to the FLOAT position to allow the body to rest on the frame. HOLD position - Move the hoist control to the HOLD position to hold the body in the current position when raising or lowering. NOTE: The hoist lever must be in the HOLD position to start the engine. RAISE position - Move the hoist control to the RAISE position to raise the body. Hold the hoist control fully back for maximum raising speed. Reduce hand force on the hoist control to reduce the speed. Hold the hoist control back until the body is raised. Release the hoist control when the body is raised. The hoist control will return to the HOLD position.
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The hoist lever has the following three positions on ejector trucks: Eject - Pull the ejector control back to the EJECT position to eject the load. Pull the ejector control fully backward for the maximum speed of the ejector blade. Hold the ejector control in the EJECT position until the ejector blade has reached full travel. Release the ejector control when the ejector blade has reached full travel. The ejector control will automatically move back to the HOLD position. Hold - When the ejector control is in the HOLD position the ejector blade is held in position by the ejector cylinder. Retract - Push the ejector control forward to the RETRACT position to return the ejector blade to the stowed position. The ejector control must be in the RETRACT position before the transmission can shift out of first gear. Always operate the machine with the ejector control in the RETRACT position to prevent damage to the ejector cylinder. NOTE: If the ejector control is in the RETRACT position, the system must be reset before you start the engine. The engine will not start if the ejector control is not in the HOLD position. To reset the system, move the ejector control to the HOLD position before starting the engine. Once the engine has been started, move the ejector control to the RETRACT position. There is a position that is forward of the RETRACT position. There is no detent in this forward position, which has no function. The transmission shift control lever (2) is also located on the right side of the operator seat. Also shown is the parking brake control knob (3). The transmission has eight forward gears, the neutral position, and one reverse gear. The transmission control incorporates the following three switches: - High gear switch (4) - Neutral lock button (5) - Transmission hold switch (6) The high gear switch allows the operator to select the upper gear limit for the transmission. The transmission hold switch allows the operator to hold the transmission in the gear that is currently engaged.
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The neutral lock button prevents the transmission control from being accidentally moved. Depress the neutral lock button to move the transmission control from the NEUTRAL position. The neutral lock button also prevents the transmission control from being moved into the NEUTRAL position from the DRIVE position or from the REVERSE position. - 735 B1N is equipped with eight forward gears and one reverse gear. - 740 B1P and B1R Ejector are equipped with seven forward gears and two reverse gears.
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The relay panel is located to the right rear of the operator’s seat. The relay functions are as follows: - Relay (1) is used to energize the backup alarm. - Relay (2) is used to energize the windshield wiper motors. - Relays (3) and (4) are main power relays. - Relay (5) is used to energize the secondary steering motor. - Relay (6) is used to energize the horn. The plug (7) is used for connecting Product Link. The plug (8) is used for Cat ET. The port (9) is used for 12 VDC accessories.
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MACHINE ELECTRONIC CONTROL SYSTEM BLOCK DIAGRAM Cluster Display Transmission and Chassis Control A4:M1
Messenger Module (Optional SEA) Engine Control A4:E1
CAN Bus CDL
Machine Control and Transmission Control Sensor Inputs
Transmission and Machine Control Outputs
Product Link Service (Optional) Port
Engine Control Inputs
Engine Control Outputs
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MACHINE ELECTRONIC CONTROL SYSTEM The Machine Electronic Control System on the Articulated Dump Trucks monitors various machine systems and then conveys the machine status to the operator. The Machine Electronic Control System includes the instrument cluster, an Engine ECM, and a Transmission/Chassis ECM. The Messenger Module is available as an optional Service Enabled Attachment (SEA) to convey additional information to the operator. The instrument cluster is a cab display that shows the operator the status of various machine parameters and alerts the operator of specific machine conditions. The instrument cluster is driven by the Transmission/Chassis Control ECM and the Engine ECM via the Controller Area Network (CAN) Data Link. The Messenger Display is an LCD module with four operator actuated pushbuttons which will allow the operator to access menus to display machine status along with operator information. The Messenger Display is driven by the Transmission/Chassis ECM and the Engine ECM over the Cat Data Link (CDL).
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Messenger Display Shown is the Messenger Display located in the right side of the front dash. The purpose of the Messenger is to display relevant machine information to the operator or service personnel. The Messenger Display is used in conjunction with the Instrument Cluster to act as the monitoring system for the machine. NOTE: The Messenger Display is an attachment. It is not necessary for the Messenger Display to be installed for the Instrument Cluster to be used as the monitoring system. The Messenger has a menu structure that allows the user to access the desired machine information. The default screen will display under normal machine operating conditions without any intervention from the operator or service personnel. The Messenger screen will display information after machine power-up and selection of any registered operator from the "operator" menu. The default screen displays a digital clock; and upon pressing the "OK" button, the Messenger will display the "Main Menu" options.
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The Messenger consists of the display (1) and four navigation buttons that are used to navigate through the menu structure. The button functions are: Back (2): Used to navigate to the previous screen that was accessed in the Messenger. Left/Up (3): Allows the user to scroll left or up. Scroll direction is dependent on the specific data that is being displayed on the screen. Right/Down (4): Allows the user to scroll right or down. Scroll direction is dependent on the specific data that is being displayed on the screen. OK (5): Acts as a confirmation function for the Messenger.
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Messenger Menu Screen The Messenger Menu Screen is divided into three sections. The field (1) identifies the name of the current menu. If the current name is split by a colon":" then this indicates that the name after the colon ":" is the current menu and the name before the colon ":" is the parent menu of the current menu. The field (3) displays the current menu option that can be selected by pressing the "OK" button. The arrows (2) indicate whether you can scroll to the next screen to see further menu options.
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Messenger Information Screens A typical Messenger Information screen is divided into three sections. Information is normally displayed in pairs. The information can be arranged horizontally, or vertically. The fields (1) identify the information and the fields (3) display the current values of the information. The arrows (2) indicate whether you can scroll to the next screen to see further information.
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MESSENGER MAIN MENU SELECTIONS Performance
Operator
Main Menu
Totals
Settings
Service
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Messenger Main Menu The menu structure for Messenger is arranged in a stair step, or hierarchical list format. When the operator, or technician, selects an option from a menu, the resulting screen is one level down from that selection. More selections or options, may be available. There may be more than one page of information or options to be displayed from any level. These levels can be accessed by using the left, right, up, or down arrow as necessary depending on how the data or list is arranged. The following options are available from the Messenger's Main Menu screen: - Performance - Operator - Totals - Settings - Service
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Performance Menu The Performance Menu allows the operator or technician to monitor vital system information during machine operation. The Performance Menu information is view only and shows the real time status of various machine systems. To access the Performance Menu from the Main Menu, press the appropriate "Arrow" button until the "Performance" option is highlighted. With the "Performance" option highlighted, press the "OK" button.
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PERFORMANCE MENU SELECTION
Performance
Engine speed
Ground Speed
Eng Coolant Temp
Shift Lever
Torque Conv Temp
Fuel Level
Actual Gear
Trans Hold Status
Battery Voltage
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Performance Menu Options The Performance Menu options are as follows: - Engine Speed:
This option will show the engine rpm.
- Ground Speed:
This option will show the ground speed in Miles per Hour or in Kilometers per Hour.
- Engine Coolant Temp:
This option will show the engine coolant temperature in degrees Fahrenheit or in degrees Celsius.
- Shift Lever:
This option will show the position of the shift lever.
- Torque Conv Temp:
This option will show the torque converter oil temperature in degrees Fahrenheit or in degrees Celsius.
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- Fuel Level:
This option will show the amount of fuel that is measured in the fuel tank as a percentage of a full tank.
- Actual Gear:
This option will show the gear that is currently engaged in the transmission.
- Trans Hold Status:
This option will show the status of the transmission hold.
- Battery Voltage:
This option will show the battery voltage.
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Operator Menu The Operator Menu is available to allow the operator to select the operator’s name from the list of registered operators. If the current operator is not registered within the Messenger system, the operator is allowed to edit an empty position, or edit an existing operator’s name. Activating any operator will reset the "Cycle Data" and "Operator Totals" within the "Totals" menu. If the back button is selected while at the "Operator" screen, the Messenger system will return back to the "Performance" menu. The Messenger system will continue to record "Cycle Data" and "Operator Totals" from the last operation of the machine.
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OPERATOR MENU SELECTION
Accept
Cancel Activate Operator Name
Lower Case Letters Edit Name
Operator
Empty Position
Upper Case Letters
Empty Position
Numbers
Empty Position
Symbols
Please Choose an Operator
Empty Position
Empty Position
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Operator Menu Options The Operator Menu options are as follows: - Please Choose An Operator:
This option will show the list of operators that have been registered on the Messenger system and the empty positions for the names of new operators. To select a registered operator, or an empty position, use the scroll up/left button or the scroll down/right button to highlight your choice and then select your choice with the "OK" button.
- Activate:
Press the "OK" button to activate the selected operator.
- Edit Name:
This option allows the names of registered operators to be edited, or to enter new names.
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Press the "OK" button to change the name of the selected operator or to enter a new name. Use the scroll up/left button and the scroll down/right button to highlight one of the following choices: - Accept - Cancel - Lower Case Letters - Upper Case Letters - Numbers - Symbols Once the desired choice is highlighted, press the "OK" button to enter the choice in the selected part of the name of the operator. Press the "Back" button anytime to move the cursor on the screen. Select the "Accept" option to return to the "Please Choose An Operator" screen with the new name, or the changed name, in the system. Select the "Cancel" option to return to the "Please Choose an Operator" screen but without making any changes to the names in the system.
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Totals Menu The totals menu receives data and then displays that information within the following additional menu options: - Cycle Data - Operator Totals - Jobsite Totals - Lifetime Totals After an operator is activated, the Messenger system will start to calculate all of the "Operator Totals." Whenever an operator’s name is activated with the Messenger, all the totals are zeroed. For proper operation of the system, an operator needs to be activated with the Messenger at the start of work. The system resets the "Cycle Data" and "Operator Totals" when an operator is activated on the system. NOTE: If complete "Cycle Data" and "Operator Totals" history is desired, do not use "Activate" in the "Operator" menu. Also, previous "Cycle Data" and "Operator Totals" for all operators can be accessed by using Cat ET version 2005A or later.
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Total Load Cnt
TOTALS MENU SELECTIONS
Loads / Hr Wait Time / Cycle
Cycle Data Total Time / Cycle Distance / Cycle
Total Load Cnt Total Fwd Dist Trav Total Rev Dist Trav Max Idle Time
Fuel / Cycle Machine Hrs
Operator Totals Totals
Total Load Cnt
Total Fuel
Total Fwd Dist Trav
Total Load Cnt
Total Rev Dist Trav
Total Fwd Dist Trav
Max Idle Time
Total Rev Dist Trav
Machine Hrs
Max Idle Time
Total Fuel
Machine Hrs
Jobsite Totals
Lifetime Totals Total Fuel
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Totals Menu Options Use the scroll up/left button and the scroll down/right button to move between the various screens and use the "Back" button to return to the "Totals" Menu. For the purpose of incrementing the load counter, a single load is counted when forward travel at a minimum specific speed of 5 km/h (3.1 mph) is followed by a body raise function of more than five seconds. The Messenger system will interpret second and subsequent loads on a regular cycle. Cycle data that is displayed by the Messenger system will be the average of these cycles. The calculation of machine idle time is based on the combination of the following factors: the machine is stationary with the hoist in the FLOAT position and the engine is running.
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Cycle Data - Total Load Cnt:
This option displays the number of times that the machine discharged a load.
- Loads/hr:
This option displays the average number of loads per hour.
- Wait Time/Cycle:
This option displays the average machine idle time per cycle.
- Total Time/Cycle:
This option displays the average machine cycle time.
- Distance/Cycle:
This option displays the average distance that was travelled per cycle.
- Fuel/Cycle:
This option displays the average amount of fuel that was used per cycle, shown in liters or US gallons.
Operator Totals Use the scroll up/left button and the scroll down/right button to move between the various screens and use the "Back" button to return to the "Totals" Menu. When an operator is activated with the Messenger system, all of the values are zeroed. The Messenger system resets the "Operator Totals" when an operator is activated on the system. NOTE: If complete "Cycle Data" and "Operator Totals" history is desired, do not use "Activate" in the "Operator" menu. Also, previous "Cycle Data" and "Operator Totals" for all operators can be accessed by using Cat ET version 2005B or later. - Total Load Cnt:
This option displays the number of times that the machine has discharged a load since the activation of the current operator.
- Tot Fwd Dist Trav:
This option displays the distance that the machine has driven in forward gear since the activation of the current operator.
- Tot Rev Dist Trav:
This option displays the distance that the machine has driven in reverse gear since the activation of the current operator.
- Max Idle Time:
This option displays the time that the machine has been stationary with the hoist in the FLOAT position and with the engine running.
- Machine Hrs:
This option displays the number of hours that the machine has been operating since the activation of the current operator.
- Total Fuel:
This option displays the information about the fuel consumption of the machine since the activation of the current operator.
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Jobsite Totals The "Jobsite Totals" menu option is intended to be used by dealers and rental fleet customers to help manage their machines. Use the scroll up/left button and the scroll down/right button to move between the various screens and use the "Back" button to return to the "Totals" Menu: NOTE: Cat ET version 2005B or later is required to zero the counters. Also, a password must be set within Cat ET to zero the "Jobsite Totals."
- Total Load Cnt:
This option displays the number of times that the machine has discharged a load on the current jobsite.
- Tot Fwd Dist Trav:
This option displays the distance that the machine has driven in forward gear on the current jobsite.
- Tot Rev Dist Trav:
This option displays the distance that the machine has driven in reverse gear on the current jobsite.
- Max Idle Time:
This option displays the time that the machine has been stationary with the hoist in the FLOAT position and with the engine running on the current jobsite.
- Machine Hrs:
This option displays the number of hours that the machine has been operating on the current jobsite.
- Total Fuel:
This option displays the information about the fuel consumption of the machine on the current jobsite.
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Lifetime Totals Use the scroll up/left button and the scroll down/right button to move between the various screens and use the "Back" button to return to the "Totals" Menu. NOTE: These totals cannot be zeroed without a factory password. - Total Load Cnt:
This option displays the number of times that the machine has discharged a load during the machine's lifetime.
- Tot Fwd Dist Trav:
This option displays the distance that the machine has driven in forward gear during the machine's lifetime.
- Tot Rev Dist Trav:
This option displays the distance that the machine has driven in reverse gear during the machine's lifetime.
- Max Idle Time:
This option displays the time that the machine has been stationary with the hoist in the FLOAT position and with the engine running during the machine's lifetime.
- Machine Hrs:
This option displays the number of hours that the machine has been operating during the machine's lifetime.
- Total Fuel:
This option displays the information about the fuel consumption of the machine during the machine's lifetime.
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Text Reference
20
Settings Menu The settings menu displays information within the following additional menu options: - Monitoring System - Transmission The settings menu allows for adjustment and viewing of various parameters for the Messenger System and the Transmission System. Several "Monitoring System" parameters are adjustable, but Cat ET is required to change any parameters in the Transmission/Chassis ECM. Use the scroll up/left button and the scroll down/right button to move between the various screens and use the "Back" button to return to the "Main Menu."
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SETTINGS MENU SELECTION Language Monitoring System Units
Top Gear Limit Body Float Gr Lmt Load Dump Min Grd Spd
Contrast Equipment No. Backlight Settings
Identification No. Trans Serial No. Top Dr Gr Sw
Info Unit Status
Machine Hours
Transmission
Distance Travelled
21
Settings Menu Options Monitoring System - Language:
Select this option to change the language that is shown on the display. Currently English, Spanish, German, and French languages are available.
- Units:
Select this option to choose either the US or the Metric measurement system.
- Contrast:
Select this option to adjust the contrast of the display. This will improve the visibility of the information. The display provides a bar graph for viewing adjustments.
- Backlight
Select this option to adjust the backlighting of the display. This will improve the visibility of the information. The display provides a bar graph for viewing adjustments.
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Transmission - Top Gear Limit:
This option displays the top gear limit for the machine. The transmission will not normally shift above the top gear limit.
- Body Float Gr Lmt:
This option displays the body float gear limit for the machine. The transmission will not normally shift above the body float gear limit with the hoist control lever out of the FLOAT position.
- Load Dump Min Grd Spd:
This option indicates the minimum ground speed that must be achieved to register a discharged load as a complete cycle.
- Equipment No:
This option indicates the equipment number that is stored in the Transmission/Machine Control ECM.
- Identification No:
This option indicates the identification number that is stored in the Transmission/Machine Control ECM.
- Trans Serial No.:
This option indicates the transmission serial number that is stored in the Transmission/Machine Control ECM.
- Top Dr Gr Sw:
This option indicates whether the switch for the top drive gear is depressed or the switch is not depressed.
- Info Unit Status:
This option shows the units that are used by the Transmission/Machine Control ECM.
- Machine Hours:
This option shows the total number of machine hours that are recorded on the Transmission/Machine Control ECM.
- Distance Travelled:
This option shows the total distance that the machine has travelled and is recorded in the Transmission/Machine Control ECM.
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Text Reference
22
Service Menu The service menu allows the operator or technician to access various service options as listed below: - View active and logged events and diagnostic codes - View the status of machine system parameters - View the status of system information Use the scroll up/left button and the scroll down/right button to move between the various screens and use the "Back" button to return to the "Main Menu."
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Text Reference
SERVICE MENU SELECTIONS Diagnostics/ Events
SRC Code OCC Act Engine
Service System Parameters
System Info
Monitoring System
System Info: Mon Sys
Engine
System Info: Engine
Chassis
System Info: Chassis
Transmission
Engine Spd / Desired Eng Spd Throttle Position / Engine Load Factor Boost Prs / Turbo Outlet Prs Fuel Pressure (ga) / Atmos Prs Oil Prs (abs0) / Oil Prs Inlet Air Temp / Fuel Temp Engine Coolant Temp / Fuel Position Rated Fuel Limit / FRC Fuel Limit Diagnostic Clock TOS/Action Alarm St / Trans Hold Status Trans Output Spd1 / Trans Output Spd2 Torque Converter Speed / Eng Speed (T/C ECM) Ground Speed / Lockup Clutch Status Retarder Lvr Pos / Hold Lamp Status Primary Steer Prs / Primary Steer WI Sec Steer Relay / Sec Steer WI Ignition SW Status / Starter Relay St Backup Alarm St / Charging Sys WI Diff Lock Sw / Crs Axle Lck Sel Sw Crs Axle Lck Sol St/Int Axle Dif Sol St Diff Lock Lamp St O/P Tran Gr Temp O/P Tran Gr Fit O/P Tran Gr Prs / Trans Oil Temp Harness Code / HC Input line 0 HC Input line 1 / HC Input line 2 HC Input line 3 / HC Input line 4 Action Lamp St / Battery Voltage Hoist Low Val Adj/Hoist Sys Enable Status
Hoist
Hoist Lever Mode/Hoist Lever % Hoist Output Hoist Low Sol Curr Hoist Not In Flt Wi Hoist Raise Sol Curr
Brake
Park Brake / Service Brake Park Brake Sw St Oper Serv Brk Prs
Shift
Shift Lever / Shift Lever % Actual Gear Top Dr Gr Sw
Filter
Fuel Filter Status / Trans Oil Flt OTG Flt / Hyd Oil Flt By Steer Oil Flt By / Air Flt
23
Service Menu Options - Diagnostics/Events:
Select this option to view events that are logged by the monitoring system.
System Parameters Use the scroll up/left button and the scroll down/right button to move between the various screens and use the "Back" button to return to the Service Menu. Engine - Engine Speed:
This option displays the engine rpm.
- Desired Engine Speed:
This option displays the desired engine speed.
- Throttle Position:
This option displays the throttle position.
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Service Menu Options - continued - Engine Load Factor:
This option displays the engine load factor.
- Boost Prs:
This option displays the boost pressure.
- Turbo Outlet Prs:
This option displays the turbocharger outlet pressure.
- Fuel Pressure (ga):
This option displays the fuel pressure.
- Atmos Prs:
This option displays the atmospheric pressure.
- Oil Prs (abs):
This option displays the absolute engine oil pressure.
- Oil Prs:
This option displays the engine oil pressure.
- Inlet Air Temp:
This option displays the inlet air temperature.
- Fuel Temp:
This option displays the fuel temperature.
- Engine Coolant Temp:
This option displays the coolant temperature.
- Fuel Position:
This option displays the fuel position.
- Rated Fuel Limit:
This option displays the rated fuel limit.
- FRC Fuel Limit:
This option displays the FRC fuel limit.
- Diagnostic Clock:
This option displays the diagnostic clock.
Transmission - TOS:
This option displays the transmission output speed.
- Action Alarm St:
This option displays the status of the action alarm.
- Trans Hold Status:
This option displays the status of the transmission hold.
- Trans Output Spd:
This option displays the speed that is recorded by transmission output speed 2.
- Torque Conv Speed:
This option displays the torque converter speed.
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Service Menu Options - continued - Eng Speed (T/C ECM):
This option displays the engine speed that is measured by the Transmission/Machine Control ECM.
- Ground Speed:
This option displays the machine ground speed.
- Lockup Clutch Status:
This option displays the status of the lockup clutch.
- Retarder Lvr Pos:
This option displays the position of the retarder lever.
- Hold Lamp Status:
This option displays the status of the hold lamp.
- Primary Steer Prs:
This option displays the primary steering pressure.
- Primary Steer WI:
This option displays the status of the warning indicator for the primary steering.
- Sec Steer Relay:
This option displays the status of the secondary steering relay.
- Sec Steer WI:
This option displays the status of the secondary steering warning indicator.
- Ignition SW Status:
This option displays the status of the ignition switch.
- Starter Relay St:
This option displays the status of the starter relay.
- Backup Alarm S:
This option displays the status of the back-up alarm.
- Charging Sys WI:
This option displays the status of the warning indicator for the charging system.
- Diff Lock S:
This option displays the status of the differential lock switch.
- Crs Axle Lck Sel Sw:
This option displays the status of the switch for the cross axle lock selector.
- Crs Axle Lck Sol St:
This option displays the status of the solenoid for the cross axle lock.
- Int Axle Dif Sol St:
This option displays the status of the solenoid for the inter axle differential.
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Service Menu Options - continued - Diff Lock Lamp St:
This option displays the status of the differential lock lamp.
- O/P Tran Gr Temp:
This option displays the status of the temperature switch for the oil in the output transfer gear.
- O/P Tran Gr Flt:
This option displays the status of the filter for the output transfer gear.
- O/P Tran Gr Prs:
This option displays the oil pressure for the output transfer gear.
- Trans Oil Temp:
This option displays the transmission oil temperature.
- Harness Code:
This option displays the harness code.
- HC Input Line 0:
This option displays the status of the harness code input.
- HC Input line 1:
This option displays the status of the harness code input.
- HC Input Line 2:
This option displays the status of the harness code input.
- HC Input Line 3:
This option displays the status of the harness code input.
- HC Input Line 4:
This option displays the status of the harness code input.
- Action Lamp St:
This option displays the status of the action lamp.
- Battery Voltage:
This option displays the battery voltage.
- Hoist Low Val Adj:
This option indicates the adjustment for the float position.
- Hoist Sys Enable status:
This option displays the installation status of the hoist system.
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Text Reference
Service Menu Options - continued Hoist - Hoist Lever Mode:
This option displays the hoist lever position.
- Hoist Lever %:
This option displays the control signal for the hoist lever displayed as a percentage of a full PWM signal.
- Hoist Output:
This option displays the status of the solenoid valves for the hoist control valve.
- Hoist Low Sol Curr:
This option displays the hoist lower solenoid current displayed as a percentage of maximum current.
- Hoist Not In Flt WI:
This option displays the status of the warning indicator for the "hoist not in float."
- Hoist Raise Sol Curr:
This option displays the hoist raise solenoid current displayed as a percentage of maximum current.
Brake - Park Brake:
This option displays the status of the system for the parking brake.
- Service Brake:
This option displays the status of the system for the service brake.
- Park Brake Sw St:
This option displays the status of the parking brake switch.
- Oper Serv Brk Prs:
This option displays the status of the pressure switch for the service brake.
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Service Menu Options - continued Shift - Shift Lever:
This option displays the position of the shift lever.
- Shift Lever %:
This option displays the control signal for the shift lever displayed as a percentage of a full PWM signal.
- Actual Gear:
This option displays the actual gear that is currently engaged in the transmission.
- Top Dr Gr Sw:
This option displays the status of the switch for the top drive gear.
Filter - Fuel Filter status:
This option displays the status of the fuel filter. This option will indicate if the fuel filter is bypassed. If the filter bypass switch is not installed within the machine configuration, the Messenger system will display "****".
- Trans Oil Flt:
This option displays the status of the oil filter for the transmission.
- OTG Flt:
This option displays the status of the filter bypass for the output transfer gear.
- Hyd Oil Flt By:
This option displays the status of the hydraulic oil filter. This option will indicate if the hydraulic oil filter is bypassed. If the filter bypass switch is not installed within the machine configuration, the Messenger system will display "****".
- Steer Oil Flt By:
This option displays the status of the steering oil filter. This option will indicate if the steering oil filter is bypassed. If the filter bypass switch is not installed on your machine configuration, the Messenger system will display "****".
- Air Flt:
This option displays the status of the bypass for the engine air filter.
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Text Reference
Service Menu Options - continued System Information Use the scroll up/left button and the scroll down/right button to move between the various screens and use the "Back" button to return to the Service Menu. - Monitoring System:
This screen displays information about the Messenger ECM hardware part number and software part number.
- Engine:
This screen displays information about the Engine ECM hardware part number and software part number.
- Chassis:
This screen displays information about the Transmission/Chassis ECM hardware part number and software part number.
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Text Reference
24
C15 ACERT™ ENGINE The C15 ACERT™ engine utilizes the A4:E4 V2.0 Electronic Control Module (ECM) engine control and is equipped with an Air to Air Aftercooler (ATTAC) intake air cooling system. The C15 engine is an in-line six-cylinder arrangement with a displacement of 7.2 L. The C15 engines are electronically configured to provide constant net horsepower through the operating ranges. Constant net horsepower automatically compensates for any parasitic loads, allowing the operator to maintain a constant level of productivity. The C15 engine installed in the 735 Articulated Dump Truck is rated at 287 kW or 385 net horsepower. The C15 engine installed in the 740 Articulated Dump Truck is rated at 325 kW or 436 net horsepower. C15 ACERT™ Technology provides an advanced electronic control, provides precision fuel delivery, and provides refined air management. The Engine ECM utilizes the Advanced Diesel Engine Management (ADEM IV) to control the fuel injector solenoids and to monitor fuel injection. The fuel is delivered through the Mechanically Actuated Electric Unit Injection (MEUI) system. The C15 ACERT™ is equipped with a wastegate turbocharger which provides higher boost over a wide range, improving engine response and peak torque, as well as outstanding low-end performance.
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With the change from Tier II engines to Tier III engines, Caterpillar offers engines with ACERT™ technology, larger displacement configurations, and air to air after cooling while providing additional horsepower. Larger displacement contributes to longer life engines, extended repair and maintenance intervals, and lower repair and maintenance costs resulting in lower cost per ton. The C15 engines are designed to meet EPA Tier III/EU Stage IIIa Emission Specifications for the U.S. and Europe through 2010. The C15 engine is also equipped with the engine compression brake. The compression brake provides extra braking effort on downhill grades where the engine acts like a power absorbing air compressor producing no additional heat.
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Text Reference
700 SERIES ARTICULATED TRUCKS ENGINE FEATURES - Engine Speed Governing - Fuel Limiting - Fuel Injection Timing Control - Ether Start Control - Engine Monitoring - Voltage Monitoring - Security - Other Machine Features
25
Engine Speed Governing: This feature includes E-trim, cranking mode, acceleration delay on startup, cool engine elevated idle, dual passive engine speed sensors, and throttle positioning which determines the desired engine speed. Fuel limiting: This feature provides torque limit non-variable HP, torque fuel temperature compensation, air fuel ratio control, cold mode running limit, cranking limit, and altitude derate. Fuel injection timing control: This features fuel injection timing with E-trim and cranking mode, transient timing, and ramped advance on acceleration timing. The timing varies with coolant temperature, inlet air temperature, and cranking timing. Ether start control: This feature is continuous flow and has the disable option via Cat ET. Engine monitoring: This feature monitors engine overspeed, high coolant temperature, and low oil.
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Voltage monitoring: This feature monitors the analog sensor supply, the digital sensor supply, and the ECM supply voltage. Security: This feature includes ECM/PM interlock, customer parameter tattletales, last service tool serial numbers, and three-level passwords. Other machine features: The engine electronic control system software also provides: - Ground level shutdown - Fuel consumption - Active and logged diagnostics - Events (overspeed, high coolant temperature, low oil pressure, engine shutdown)
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Text Reference
CAT Data Link
A4-E4 Engine ECM
15
20 25
10
5
X100 n/min
0
CAN Data Link
EUI Injectors (6)
30
35
2.3
1F
132.1
Instrument Cluster
Throttle Pedal Position Sensor Timing Cal Probe Connector Ground Level Shutdown Switch
Intake Manifold Air Temperature Engine Coolant Temperature
Variable Speed Fan Solenoid
Crank Speed / Timing Sensor 1 and 2 Brake Solenoid
Cam Speed / Timing Sensor Intake Manifold Air Pressure
3 and 4 Brake Solenoid
Engine Oil Pressure Sensor
5 and 6 Brake Solenoid
Atmospheric Pressure Sensor Key Start Switch
Fuel Temp Sensor Fuel Pressure Sensor
Ether Start Solenoid
Fuel Differential Pressure Switch
26
Engine Electrical Block Diagram This block diagram of the engine electrical system shows the components which provide input signals to and receive output current from the Engine ECM. Based on the input signals, the Engine ECM energizes the Mechanically Actuated Electronic Unit Injectors (MEUI) to control fuel delivery to the engine. A solenoid on each unit injector controls the amount of fuel delivered by the unit injector. The Engine ECM provides a signal to each unit injector solenoid to control the fuel injection. The system also monitors other functions that are critical for engine performance. The two machine interface connectors provide electrical connections from the engine to the Transmission/Chassis ECM over both the CAN Data Link and the Cat Data Link. Some of the components connected to the Engine ECM through the machine interface connectors are: the throttle pedal position sensor, the ether aid solenoid, and the ground level shutdown switch.
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Text Reference
Input Components: Atmospheric pressure sensor - This sensor is an input to the Engine ECM and is used as a reference for the pressure sensors. Also, the sensor is used to supply information to the Engine ECM during operation at high altitudes. Intake manifold air temperature sensor - This sensor is an input to the Engine ECM to supply information about the air temperature in the intake manifold. Intake manifold air pressure sensor - This sensor is an input to the Engine ECM supplying air pressure (boost) in the intake manifold. Fuel differential pressure switch - This switch relays information to the ECM that the fuel pressure at the output of the filter base is restricted in comparison to the inlet pressure. Engine coolant temperature sensor - This sensor is an input to the Engine ECM to supply information on the coolant temperature. Engine oil pressure sensor - This sensor is an input to the Engine ECM to supply information on engine oil pressure. Throttle pedal position sensor - This sensor relays the position of the throttle to the Engine ECM in order to increase or decrease the fuel supply to the injector. Ground level shutdown switch - This switch is an input to the Engine ECM. This input disables fuel injection when the engine is running or at engine start-up. Crank and cam speed/timing sensors - These speed sensors are passive speed sensors that provide a signal similar to a sine wave that varies in amplitude and frequency as speed increases. The permanent timing calibration sensor monitors the speed and position of the flywheel. Key start switch - The key start switch "ON" sends + voltage to the electrical system. Fuel temperature sensor - The sensor sends fuel temperature feedback data to the Engine ECM. Fuel pressure sensor - The sensor sends fuel pressure feedback data to the Engine ECM. Timing calibration connector - The TDC probe is used for Engine Speed/Timing Sensor Calibration if the Engine ECM is flashed or replaced. Manual ether start switch - This switch is an input to the Engine ECM to energize the ether start relay to send continuous ether flow to the intake manifold.
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Output Components: 1 & 2 Brake solenoid - This solenoid directs engine oil to the master piston and slave piston for No. 1 and No. 2 injectors and exhaust rocker arms. 3 & 4 Brake solenoid - This solenoid directs engine oil to the master piston and slave piston for No. 3 and No. 4 injectors and exhaust rocker arms. 5 & 6 Brake solenoid - This solenoid directs engine oil to the master piston and slave piston for No. 5 and No. 6 injectors and exhaust rocker arms. Mechanically Actuated Electronic Unit Injectors (6) - Injectors supply a governed amount of fuel to the basic engine. Ether start solenoid - This solenoid supplies a continuous flow of ether when the correct parameters are present in the Engine ECM. Instrument cluster - The instrument cluster receives signals from the Engine ECM and Transmission/Chassis ECM on the CAN Data Link and supplies various information through warning indicators, action alarms, LCD readouts, and gauge indicators.
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Text Reference
27
The Engine Electronic Control Module (ECM) is the central component in the Engine Management System. The A4:E4 Electronic Control Module (ECM) is located at the left rear of the engine. The A4:E4 ECM is equipped with a 120 pin connector (J-2) and a 70 pin connector (J-1). Be sure to identify which connector is the J1 or J2 connector before performing diagnostic tests. The ECM makes decisions based on switch-type and sensor input signals and memory information. Input signals to the ECM come from the control station, and the sensors on the engine and engine support systems. The Engine ECM computes the data sent over the CAN Data Link or the CAT Data Link. The ECM input components are the crank and cam speed/timing sensors, the pressure sensors, and the temperature sensors. The ECM output components are the six injectors and the compression brake solenoids. The Engine ECM responds to engine inputs by sending a signal to the appropriate output component to initiate an appropriate action. For example, if the Engine ECM receives a high coolant temperature signal, the Engine ECM interprets the input signal, evaluates the current operating status, and derates the fuel supply under load, if necessary.
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Text Reference
The Engine ECM receives three different types of input signals: 1. Switch input: Provides the signal line to battery, ground, or open. 2. PM input: Provides the signal line with a square wave of a specific frequency and a varying positive duty cycle. 3. Speed signal: Provides the signal line with either a repeating, fixed voltage level pattern signal, or a sine wave of varying level and frequency. The Engine ECM has three types of output drivers: 1. ON/OFF driver: Provides the output device with a signal level of +Battery voltage (ON) or less than one Volt (OFF). 2. PM driver: Provides the output device with a square wave of fixed frequency and a varying positive duty cycle. 3. Controlled current output driver: The ECM will energize the solenoid with pull-up current for a specific duration and then decrease the level to hold-in current for a specific duration of the on time. The initial higher amperage gives the actuator rapid response and the decreased level is sufficient to hold the solenoid in the correct position. An added benefit is an increase in the life of the solenoid. The Engine ECM has built-in diagnostic capabilities. As the Engine ECM detects fault conditions in the power train system, the ECM logs events in memory and diagnostic codes for troubleshooting and displays them through Cat ET. Occasionally, Caterpillar will make changes to the internal software that controls the performance of the engine. These changes can be performed by using the WinFlash program in Cat ET. If using the WinFlash program, a "flash" file must be obtained from Caterpillar and uploaded to the ECM.
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Text Reference
2
1
28
If the engine requires timing calibration, a timing sensor (magnetic pickup) is installed in the engine block at location (2) and connected to the timing calibration connector (1) located above the Engine ECM. The timing calibration is performed automatically with Cat ET. The desired engine speed is set to 1100 rpm. This step is performed to avoid instability and ensures that no backlash is present in the timing gears during the calibration process. Timing calibration improves fuel injection accuracy by correcting for any slight tolerances between the crankshaft, timing gears, and timing wheel. Timing calibration is normally performed after the following procedures: - ECM replacement - Cam or crank sensor replacement - Timing wheel replacement
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Text Reference
29 1
2
30 3
The primary engine speed/timing sensor (crank) (1) is located at the bottom of the timing gear cover. The primary engine speed/timing sensor sends a frequency signal to the Engine ECM on contact J2-35 and contact J2-25 indicating crankshaft speed. The speed/timing sensors serve four functions in the engine electronic control system: 1. Engine speed measurement 2. Engine timing measurement 3. TDC location and cylinder number identification 4. Reverse rotation protection
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Text Reference
The secondary engine speed/timing sensor (cam) (2) is located at the rear of the timing gear cover on the left side of the engine. The secondary engine speed/timing sensor sends a frequency signal to the Engine ECM on contact J2-46 and contact J2-47 indicating camshaft speed. The speed/timing sensors are installed with a clearance between the sensor and the timing wheel. This clearance is not adjustable. The intake manifold pressure sensor/turbocharger outlet pressure sensor (3) is located at the front of the engine on the left side of the cylinder head. The input data from the intake manifold pressure sensor to the Engine ECM is used by the ECM to electronically control the air fuel ratio. This feature allows very precise smoke control, which was not possible with mechanically governed engines. The intake manifold pressure sensor also allows boost pressure to be read using Cat ET. The intake manifold pressure sensor/turbocharger outlet pressure sensor receives a +5 VDC signal from the Engine ECM on contact J2-72 and sends a signal to the ECM on contact J2-15.
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Text Reference
31
This illustration shows the location of the coolant temperature sensor (arrow) on the front of the engine in the water temperature regulator housing. The coolant temperature sensor monitors the temperature of the coolant in the system. The coolant sensor temperature information sent to the Engine ECM is used for Warning Levels that are sent to the monitoring system. The following diagnostic codes are logged when the engine coolant temperature sensor is damaged or malfunctioning. 0110-3 - Engine coolant temperature sensor open/short to + Bat 0110-4 - Engine coolant temperature sensor short to ground
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Text Reference
1 2
32
This illustration shows the start relay (1) and hood control relay (2). The start relay transfers power to the starter when commanded by the Transmission/Chassis ECM. The hood control relay transfers power to the hood motor to open and close the hood. The hood control relay is activated by the hood lock switch in the cab.
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Text Reference
HIGH COOLANT TEMPERATURE DERATE 120
% Derate
100 80 60 40 20 0 110
111
111.5
112
112.5
113
113.5
114
114.5
Coolant Temperature C Level 1 Warning
Level 2 Warning / Derates
33
High Coolant Temperature Derate The coolant temperature sensor measures the temperature of the coolant. When the temperature of the coolant exceeds 110° C (230° F), the Engine ECM will initiate a Level 1 Warning. When the temperature of the coolant exceeds 111° C (231° F), the Engine ECM will initiate a Level 2 Warning. At 111° C (231° F) the Engine ECM will initiate a 25% derate. Refer to the illustration for the remainder of the high engine coolant temperature derates. At 100% derate, the engine available power will be approximately 50%.
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34
The intake manifold air temperature sensor (arrow) is located on the left side of the engine. The air temperature sensor provides air temperature data on contact J2-56 to the Engine ECM to warn the operator of potentially damaging conditions. This sensor is also used for derating the engine at high temperature, for engine shutdown at high temperature, and for use by the monitoring system.
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Text Reference
C15 ENGINE INTAKE MANIFOLD TEMPERATURE DERATE 21 18
% Derate
15 12 9 6 3 0 82
86
87
88
89
90
91
92
93
Intake Manifold Temperature C Level 1 Warning
Level 2 Warning / Derates
35
Intake Manifold Air Temperature Sensor Derate The intake manifold air temperature sensor measures the temperature of the air that is flowing into the intake manifold. The sensor is used to initiate warning levels and engine derates. After the engine is running for at least 3 minutes and if the intake manifold air temperature goes above 82° C (180° F), the Engine ECM will initiate a Level 1 Warning. After the engine is running for at least 3 minutes and if the intake manifold air temperature goes above 86° C (187° F), the Engine ECM will initiate a Level 2 Warning. With the Level 2 Warning, the Engine ECM signals the engine to initiate a 3% derate. This derate will have a 20% upper limit.
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Text Reference
2
1
3
36 The atmospheric pressure sensor (1) is located on the left side of the engine. The Engine ECM uses the sensor as a reference for air filter restriction, and derating the engine under certain parameters. All pressure sensors in the system measure absolute pressure, and therefore, require the atmospheric (barometric) pressure sensor to calculate gauge pressures. Calibration can be accomplished using Cat ET or by turning on the key start switch without starting the engine for five seconds. The following diagnostic codes are logged when the atmospheric pressure sensor is damaged or malfunctioning. 0274-3 - Atmospheric pressure sensor open/short to + Bat 0274-4 - Atmospheric pressure sensor short to ground
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The engine oil pressure sensor (2) is located on the left side of the engine near the Engine ECM (3). The oil pressure sensor monitors the pressure of the engine oil. The Engine ECM will use the information supplied by the oil pressure sensor to output warning levels to the monitoring system. The following diagnostic codes are logged when the engine pressure sensor is damaged or malfunctioning. 0100-3 - Engine oil pressure sensor open/short to + Bat 0100-4 - Engine oil pressure sensor short to ground
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Text Reference
LOW OIL PRESSURE 180 160 140
kPa
120 100 80 60 40 20 0 0
500
1000
kPa Shut down Level 3
1500
2000
2500
3000
3500
rpm
kPa Warning Level 1
37
Low Oil Pressure Derate This illustration shows a graph with the two different warning levels for low oil pressure. When the oil pressure is below the blue line (154 kPa @ 1600 rpm) (22 psi @ 1600 rpm), the monitoring system will enable the low oil pressure Level 1 Warning. Change machine operation or perform maintenance to the system, in the event of a warning. When the oil pressure is below the red line (104 kPa @ 1600 rpm) (15 psi @ 1600 rpm), the monitoring system will enable the low oil pressure Level 3 Warning. The operator should immediately perform a safe engine shutdown, in the event of a Level 3 warning. Also, with the Level 3 Warning, the Engine ECM initiates a 35% engine derate. If the signal between the Engine ECM and the oil pressure sensor is lost or disabled, the Engine ECM will initiate a low engine oil pressure Level 1 Warning.
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Text Reference
VIRTUAL EXHAUST TEMPERATURE DERATE Engine Derate Percentage
Barometric Pressure Inlet Manifold Temperature Engine Speed
Fuel Injection Calibration
Highest Derate Priority Selector
Other Engine Derate Conditions
Engine ECM
38
Virtual Exhaust Temperature Derate An engine derate can occur due to a estimated (virtual) high exhaust gas temperature. The Engine ECM monitors barometric pressure, intake manifold temperature, and engine speed to estimate exhaust gas temperature. Certain conditions (high altitude, high ambient temperatures, high load and full accelerator pedal throttle, barometric pressure, intake manifold temperature, and engine speed) are monitored to determine if the engine derate should be enabled. The Engine ECM determines a maximum fuel delivery percentage to maintain safe maximum power output under load. This calculation is new to the off-road Tier III engines and is used in place of the previous altitude compensation derate strategy. This event is to inform the mechanic that a derate has occurred because of operating conditions. Generally, this is normal and requires no service action. The Engine ECM will process all derate inputs in the highest derate priority selector. The most critical derate condition input will be used to adjust fuel system delivery limiting engine power to a safe level for the conditions in which the product is being operated, thereby preventing elevated exhaust temperatures.
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Text Reference
The virtual exhaust temperature derate will log a 194 event code. The derate will enable a Level 1 Warning and eventually a Level 2 Warning. The level of the warning will depend on the conditions that are sent to the Engine ECM. The following conditions must be met to initiate a virtual exhaust temperature derate. - No CID 168 01 FMI (low battery voltage to the Engine ECM) are active. - No active intake manifold pressure sensor faults. - No active atmospheric pressure (barometric) sensor faults. - No +5 V sensor voltage codes active. - The virtual exhaust temp derate must be the highest derate. - More fuel is being requested than the virtual exhaust temp derate will allow. This derate is triggered by the information inferred by the Engine ECM, rather than an individual sensor as with the previous single derate strategies. If you think this derate is possibly being imposed incorrectly check for event codes on the high intake manifold temperature. Correct any codes first. Also, make sure the aftercooler is unobstructed. For additional information about troubleshooting, refer to the troubleshooting guide for the particular engine that is being serviced.
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1
Text Reference
2
39
The turbocharger inlet pressure sensor (1) is located in a tube between the air cleaner (2) and the turbocharger (not shown). The Engine ECM uses the turbocharger inlet pressure sensor in combination with the atmospheric pressure sensor to determine air filter restriction. The Engine ECM provides the input signal to the monitor system, which informs the operator of the air filter restriction. The sensor receives a +5 VDC signal from the Engine ECM on contact J1-2 and sends a pressure signal to the ECM on contact J1-15. The following diagnostic codes are logged when the turbo inlet air pressure sensor is damaged or malfunctioning. 1589-3 - Turbo inlet pressure sensor - turbo inlet air pressure sensor open/short to + Bat 1589-4 - Turbo inlet pressure sensor - turbo inlet air pressure sensor short to ground
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Text Reference
AIR INLET RESTRICTION DERATE 16 14
% Derate
12 10 8 6 4 2 0
0
2
4
6
8
10
12
14
16
Air Restriction kPa Difference Level 1 Warning
Level 2 Warning / Derates
40
Air Inlet Restriction Derate The turbo inlet pressure sensor measures the restriction of the air inlet that is flowing to the inlet of the compressor housing of the turbocharger. When the pressure difference between the turbo inlet pressure sensor and the atmospheric sensor read a difference of 9.0 kPa, the Engine ECM will derate the engine approximately 2%. The Engine ECM will then derate the engine 2% more for every 1 kPa difference up to 10%. Typically the atmospheric pressure sensor is 100 kPa at sea level. As the air restriction increases, the difference will increase. The first derate will occur when the difference is approximately (100 kPa minus 91 kPa = 9 kPa). If the air inlet restriction is 92.5 kPa (a pressure that is between 7.5 kPa and 9 kPa) for 30 seconds, the Engine ECM will initiate a Level 1 Warning. If the air restriction goes to the point that the turbo inlet pressure sensor sees a difference of 91.0 kPa (a pressure that is 9.0 kPa) for 30 seconds, then the Level 2 Warning will occur and the engine will going into the air inlet restriction derate.
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Text Reference
C15 ACERT ENGINE FUEL DELIVERY SYSTEM
Fuel Pressure Regulator
Fuel Gallery Primary Fuel Filter/ Water Separator
Secondary Fuel Filter
Fuel Transfer Pump
Fuel Tank
41
Fuel System Fuel is drawn from the fuel tank through the primary fuel filter and water separator by a gear-type fuel transfer pump. The fuel transfer pump then directs the fuel through the secondary fuel filter. The fuel then flows to the cylinder head. The fuel enters the cylinder head and flows into the fuel gallery, where it is made available to each of the six MEUI fuel injectors. Any excess fuel not injected leaves the cylinder head and flows back to the secondary fuel filter where it flows past the fuel pressure regulator. The fuel pressure regulator is a check valve that is installed in the secondary fuel filter. The fuel pressure regulator maintains fuel system pressure between the fuel transfer pump and the fuel pressure regulator. From the fuel pressure regulator, the excess fuel flow returns to the fuel tank. The ratio of fuel used for combustion and fuel returned to the tank is approximately 3:1 (i.e. four times the volume required for combustion is supplied to the system for combustion and injector cooling purposes).
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Text Reference
POWER DERATE Highest Rated Torque Map
50% Derate
Power
Derate 100% Derate
Default Torque Map
Engine Speed 42
Power Derate The illustration above defines the power derate in relation to the rated torque map and the default torque map. The power derate is a percentage reduction from the rated power at a given engine speed toward the default map at the same rpm. Power is unchanged until the requested power exceeds the derated level. The maximum power during a derate is calculated as: Maximum Power Output = Rated Power - (Rated Power - Default Power) * Derate Percentage For example, if the engine has a maximum rated power of 500 hp and a 100 hp default torque map with a 50% derate, the engine will produce 300 hp. If 250 hp was needed, then the operator will not notice any change. If however, 400 hp was needed, there would be only 300 hp available due to derates. 300 hp = 500 hp - (500 hp - 100 hp) X 50% (.50)
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Text Reference
43
The fuel transfer pump (arrow) is a gear pump that is located near the balancer at the front of the engine and the rear of the machine. The fuel transfer pump is driven by the front gear train through the Air To Air Aftercooler (ATAAC) pump. Fuel is drawn from the fuel tank through the primary fuel filter and water separator by the fuel transfer pump and is sent to the secondary fuel filter. The fuel transfer pump is equipped with a check valve (not shown). The check valve allows fuel to flow around the gears of the pump when the fuel system is primed. A relief valve (not shown) is also installed in the fuel transfer pump. The relief valve limits the maximum fuel pressure in the fuel system.
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Text Reference
44
The primary fuel filter (arrow) is located on the left side of the engine. The primary filter contains a water separator which removes water from the fuel. Water in a high pressure fuel system can cause premature failure of the injector due to corrosion and lack of lubrication. Water should be drained from the water separator daily, using the drain valve that is located at the bottom of the filter.
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Text Reference
1
2
45
3 4
46
The upper illustration shows the location of the secondary fuel filter (1) and base that is equipped with manual priming pump. The differential fuel pressure switch (2) is located in the top of the secondary fuel filter housing on the left side of the engine. This switch indicates restriction in the fuel filter and provides feedback to the Engine ECM through contact J2-65. A warning is also sent by the Engine ECM to the Machine Monitor System. The fuel pressure sensor (3) is used to monitor fuel pressure and receives a +5 VDC signal from the Engine ECM on contact J2-72 and sends feedback to the ECM on contact J2-40.
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Text Reference
The fuel temperature sensor (4) provides feedback to the Engine ECM on contact J2-62. The Engine ECM uses the fuel temperature measurement data from the fuel temperature sensor to disable the fuel filter restriction strategy if the fuel temperature goes below 30° C (86° F). The following diagnostic codes are logged when the fuel pressure sensor is damaged or malfunctioning. 0094-3 - Fuel pressure sensor - fuel pressure open/short to + Batt 0094-4 - Fuel pressure sensor - fuel pressure short to ground The following diagnostic codes are logged when the fuel temperature sensor is damaged or malfunctioning. 0174-3 - Fuel temperature sensor - fuel temperature open/short to + Batt 0174-4 - Fuel temperature sensor - fuel temperature short to ground
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Text Reference
FUEL TEMPERATURE DERATE 30
% Derate
25 20 15 10 5 0 89.8 90.0 90.2 90.4 90.6 90.8 91.0
91.2
91.4
91.6
91.8
92.0 92.2
Fuel Temperature C Level 1 Warning
Level 2 Warning / Derat es
47
Fuel Temperature Derate This illustration shows the graph for the warning and the derates map for the fuel temperature. When the fuel temperature exceeds 90° C (194° F), the Engine ECM will activate a Level 1 Warning and log a 363-1 Event. If the fuel temperature increases to 91.0° (196° F) a Level 2 Warning will be initiated by the Engine ECM with a 363-2 Event. At the same time, the engine will derate to 12.5%. If the fuel temperature exceeds 92° C (198° F), the engine will be derated to 25%. A fuel temperature sensor open circuit will derate the engine to 12.5%. Excessive fuel temperature may cause injector wear.
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Text Reference
FUEL FILTER RESTRICTION DERATE THE FUEL TEMP ABOVE 30 C (86 F) AND PRESSURE ABOVE 110 kPa (15 psi)
60
% Derate
50 40 30 20 10 0 0
3 min
1 hr
2 hr
Time Level 1 Warning
3 hr
4 hr
4hr 1 sec
5 hr
Level 2 Warning / Derates
48
High Fuel Filter Restriction Derate When the differential pressure switch recognizes a fuel pressure of 103 kPa (15 psi) for 1 hour, the Engine ECM will initiate a Level 1 Warning and log a 390-1 Event. When the differential pressure switch recognizes 103 kPa (15 psi) across the filter for 4 hours, the Engine ECM will initiate a Level 2 Warning and log a 390-2 Event. With the Level 2 Warning initiated, a 17.5 % derate is applied to the engine. After 1 second, the Engine ECM will initiate a second derate of 17.5%. The total derate will be 35%. This feature will be disabled when the fuel temperature is below 30° C (86° F).
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Text Reference
1 49
2
3
4
50
The throttle position sensor (4) is mounted on the throttle pedal (1). The sensor receives a +8 VDC signal from the Engine ECM. When the throttle pedal is depressed, the position sensor sends a change in the PWM signal to the Engine ECM indicating the throttle pedal position has changed. The throttle position sensor provides engine speed control for the operator. At engine start-up, the engine rpm is set to LOW IDLE for two seconds to allow an increase of oil pressure before the engine is accelerated. Also shown are the inter-axle interlock switch (2) and brake pedal (3).
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Text Reference
A functional check of the throttle control system can be performed by connecting Cat ET and monitoring the throttle position on the status screen as the throttle is moved slowly in both directions. The status screen will show between 0 and 100% of throttle position. (This reading should not be confused with the duty cycle percentage). Also a check of the Active Faults screen will verify the status of the circuit. A failure of this circuit will allow the engine to run at LOW IDLE only. The following diagnostic codes are logged when the throttle position sensor is damaged or malfunctioning. 0091-3 - Accelerator pedal - voltage above normal 0091-4 - Accelerator pedal - voltage below normal Automatic Ether Start Control The ether start control has changed with the introduction of the Tier 3 machines. The ether system (if equipped) is now automatically controlled by the Engine ECM. There is no longer a switch in the operator’s station. Ether control now utilizes one continuous shot instead of one shot application. The ECM energizes the ether solenoid in a continuous flow for a predetermined amount of time that is based on the coolant temperature and the intake manifold air temperature. The ether injection system is enabled when the following conditions are met: - Engine speed is between 35 and 650 rpm. - The colder of the coolant temperature or intake manifold air temperature must be below 0° C (32° F). Also, the automatic ether start control has a post ether injection duration. After the engine speed has reached 650 rpm, the post ether injection is activated. The Engine ECM uses the coldest of the two temperatures to decide the length in time of injection. The following is a list of duration time in seconds as a function of temperature: • 0° C (32° F): 12 sec • -10° C (14° F): 17 sec • -20° C (-4° F): 22 sec • -30° C (-22° F): 24 sec • -40° C (-40° F): 26 sec • -50° C (-58° F): 26 sec
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Text Reference
Elevated Idle Speed Feature The elevated idle speed feature allows the operator to maintain an engine speed that is between the values of the low idle and high idle without the need for operator input. This feature allows the engine to run at elevated idle for extended periods while an implement such as a water pump is being operated. The elevated idle speed can be set to any value between low idle and high idle, but the default value is 1500 rpm. The elevated idle speed is set through the Configuration Window in Cat ET. The elevated idle speed feature will be ON when all of the following conditions are met: - The accelerator control is in the low idle position. - The transmission is in NEUTRAL. - The parking brake is ON. The elevated idle speed feature will be OFF when any of the following conditions are met: - The input from the accelerator control is greater than 11%. - The transmission is not in NEUTRAL. - The parking brake is OFF.
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Text Reference
51
Engine Brake The C15 ACERT™ is equipped with an engine compression brake (arrow). The machine uses valve timing change to open the exhaust valves before TDC during the compression stroke to produce negative engine torque. The value to the machine from using the compression brake is reduced engine overspeeds, reduced brake oil temperatures, and extended brake component life. The operator selects the retarding level by moving the engine brake selector switch in the cab. The selector switch position is read by the Transmission/Chassis ECM and communicated over the CAT Data Link to the Engine ECM. The Engine ECM activates the engine brake when the following conditions are met. - The engine brake selector switch is at low, medium, or high - The engine speed is above 1000 rpm - The desired engine speed is at low idle. The engine brake will be deactivated when the engine speed is below 950 rpm and reactivated if the engine speed rises above 1000 rpm. The following cylinders are enabled when the selector switch is in the matching position. Low Medium High
(1 & 2) (1&2) (5 & 6) (1 & 2) (3 & 4) (5 & 6)
The ECM will disable injection to that cylinder while the engine brake is active.
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Text Reference
52
This illustration shows the basic principle of engine compression brake retarding. During normal engine operation without the engine brake enabled, the following actions occur: 1. Intake stroke: The intake valve opens and air is forced into the cylinder by boost pressure from the turbocharger. 2. Compression stroke: Air is compressed by the engine piston. The energy required to compress this air is produced by the vehicle's driving wheels. 3. Power stroke: When the piston passes over top dead center and begins the power stroke, the energy is returned to the piston (and to the driving wheels). Essentially no energy is absorbed and no net retarding work is done. 4. Exhaust stroke: Air is forced out through the exhaust.
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Text Reference
When the engine compression brake is activated, the following actions occur: 1. Intake stroke: The intake valve opens and air is forced into the cylinder by boost pressure from the turbocharger. 2. Compression stroke: Air is compressed to approximately 3450 kPa (500 psi) by the engine piston. The energy required to compress this air is produced by the vehicle's driving wheels. Near top dead center, the compression brake opens the exhaust valve, venting the high pressure air and dissipating the stored energy through the exhaust system. 3 Power stroke: Essentially no energy is returned to the piston (and to the driving wheels). There is a loss of energy. This loss is how the retarding work is done. 4. Exhaust stroke: Air is forced out through the exhaust.
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Text Reference
ENGINE BRAKE DISABLED
Cylinder-1 Slave Piston
Cylinder- 2
Master Piston
Solenoid Valve Injector Rocker Engine Head Pump Cylinder Pressure Exhaust Cam Lobe
Injector Cam Lobe
53
This illustration shows the engine brake disabled. The solenoid valve is de-energized by the Engine ECM. The pump draws oil from the engine sump and sends the oil to the solenoid valve, where it is blocked. Oil behind the master piston or the slave piston in either cylinder will flow through the solenoid valve and return to the engine oil sump.
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Text Reference
ENGINE BRAKE
ENABLED AND BEFORE TDC Cylinder-1 Slave Piston
Cylinder- 2
Master Piston
Solenoid Valve Injector Rocker Engine Head Pump Cylinder Pressure Exhaust Cam Lobe
Injector Cam Lobe
54
This illustration shows the engine brake enabled (the lever in the cab will be in either the high, medium, or low position). When the ECM energizes the solenoid valve, the engine oil is directed past the check valve to the master piston. As the injector rocker moves up, the master piston moves up and increases the oil pressure. The increased oil pressure forces the slave piston down. The slave piston begins to move the rocker arm against the exhaust valves.
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Text Reference
ENGINE BRAKE
ENABLED AND PISTON AT TDC Cylinder-1 Master Piston
Slave Piston
Cylinder-2 Solenoid Valve
Injector Rocker Engine Head Pump Cylinder Pressure Exhaust Cam Lobe
Injector Cam Lobe
55
This illustration shows the piston at top dead center. As the slave piston pushes down the exhaust rocker, the exhaust valves open allowing the fuel/air mixture to escape the cylinder through the exhaust valves. This will eliminate any compression in the cylinder. NOTE: When the exhaust valves open, the escaping mixture will give off an audible response.
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Text Reference
ENGINE BRAKE
ENABLED AND PISTON AFTER TDC Cylinder-1 Master Piston
Slave Piston
Cylinder- 2 Solenoid Valve
Injector Rocker Engine Head Pump Cylinder
Exhaust Cam Lobe
Injector Cam Lobe
56
This illustration shows the engine with the cam lobe after top dead center. The valve springs force the exhaust valves closed and with less oil pressure acting on the slave piston, the injector rocker rotates to the right. The oil pressure in the master cylinder chamber is decreased allowing the oil in the slave cylinder to direct the oil back into the master cylinder.
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Text Reference
57
1
3
58
2
COOLING FAN SYSTEM The cooling fan system consists of two separate fan drive systems. The ATAAC fan circuit cools the ATAAC at the front of the engine. The cooling fan circuit cools the engine coolant, the air conditioning condenser, the output transfer gear oil cooler, and the cooling fan drive circuit at the rear of the cab. The cooling fan pump is a gear pump that supplies oil to the cooling fan motor. The fan pump (1) on the 735 trucks is attached to the pump drive on top of the transmission. The fan pump (2) on the 740 trucks is attached to the steering pump (3).
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Text Reference
59
1
2 60
3
The fan motor (1) is located behind a panel at the rear of the tractor on the right side. The fan motor is driven by the fan pump oil. The fan solenoid (2) is located below the fan housing. The fan solenoid is controlled by the Engine ECM. When the solenoid receives a signal from the ECM, the solenoid directs oil to the bypass valve as necessary to control the fan speed. Also located near the fan solenoid is a remote pressure tap fitting (3) that can be used to test fan system pressure at the remote pressure tap location.
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Text Reference
1
7
6
5
3
4
2
61
The cooling fan provides air circulation to the radiator (1), the output transfer gear oil cooler (2), the air conditioning condenser (3), and the fan system oil cooler (4). The bypass valve (5) directs oil flow from the fan motor and the fan solenoid to the tank. Also visible in this illustration are the transmission breather (6) and the output transfer gear breather (7). The breathers cannot be cleaned and must be replaced when required.
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Text Reference
COOLING FAN HYDRAULIC SYSTEM
Transmission
Fan Pump (735)
Steering Pump
Fan Pump (740)
Fan Motor
Fan Solenoid
Bypass Valve Cooler
Steering and Fan Hydraulic Tank
62
This illustration shows the fan system hydraulic circuit when the engine is cold. The fan pump supplies oil to the fan motor and fan solenoid. Pump oil flow is proportional to engine speed, which determines the rotational speed of the fan motor. The fan solenoid valve diverts oil flow to the bypass valve, which decreases the fan speed when the engine is cold. The solenoid valve restricts oil flow to the diverter valve as the temperatures increases, which allows additional oil flow through the fan motor and the fan speed increases. The Engine ECM monitors the engine air inlet temperature and the engine coolant temperature and sends a corresponding signal to the fan solenoid. The fan solenoid valve is also used as a relief valve to limit the maximum fan system oil pressure. The bypass valve directs a certain amount of return oil through the oil cooler. The flow rate of oil through the oil cooler is proportional to the oil temperature. The relief valve inside the bypass valve protects the oil cooler from excessive pressure. A check valve prevents fan motor cavitation when the engine is shut off and the fan motor continues to rotate.
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Text Reference
AIR TO AIR AFTERCOOLER HYDRAULIC SCHEMATIC
Hydraulic Motor From HMU
Engine
ATAAC Pump
Relief Valve
Fuel Transfer Pump
Makeup Valve
Hydraulic Tank
63
The 735 and 740 Articulated Dump Truck engines are equipped with an Air To Air Aftercooler. The illustration above show the schematic for the ATAAC fan circuit. The ATAAC pump draws oil from the hydraulic tank on the right side of the truck and directs the oil to the hydraulic motor to rotate the fan. The hydraulic motor is part of the front radiator. The motor is equipped with a makeup valve and a relief valve. The makeup valve allows oil to recirculate tank oil through the motor when the engine is shutdown or the speed is reduced drastically eliminating cavitation in the motor. The relief valve is used to limit the pressure of the oil flowing through the motor. This relief valve is also used to control the motor speed.
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Text Reference
1 2
64
3 6 65
4
5
The upper illustration shows the ATAAC hydraulic gear pump (1). The pump is located on the left side of the engine attached to the front cover. Also shown is the fuel transfer pump (2) which is driven through the hydraulic pump. The lower illustration shows the location of the hydraulic motor (3). The motor is located at the front of the engine. Also shown are the makeup valve (4), the relief valve (5), and the pressure tap (6).
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Text Reference
735 / 740 POWER TRAIN 735 ECPC Transmission - 6 Modulating Solenoid Valves - 6 Hydraulic Clutches - 8 Forward Speeds / 1 Reverse Speed 740 ICM Transmission - 1 Upshift Solenoid / 1 Downshift Solenoid - 7 Hydraulic Clutches - 7 Forward Speeds / 2 Reverse Speeds
66
POWER TRAIN The 735 Articulated Truck uses an Electronic Clutch Pressure Control (ECPC) Transmission. Six ECPC solenoid valves control oil flow to the individual hydraulic clutches to provide eight forwards speeds and one reverse speed. The Transmission/Chassis ECM receives input signals from various switches and sensors, processes the signal information, and sends output signals to the ECPC solenoid valves to control transmission shifting. The 735 transmission system is similar to the ECPC transmission system used on the 725/730 Articulated Trucks. The 740 Articulated Truck uses an Individual Clutch Modulation (ICM) power shift transmission. An upshift solenoid and a downshift solenoid control oil flow to the transmission rotary actuator, which shifts the transmission. The 740 ICM transmission has seven forward speeds and two reverse speeds. The 740 transmission system is similar to the ICM transmission system used on the "D" and "E" Series Off-highway Trucks. The 735 and 740 output transfer gear and differential systems are similar and will be covered together.
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Text Reference
2 3 4
4
1
4
4 8 7
6
4 5
67
The power train system in the 735/740 Articulated Dump Trucks uses power that is developed by the C15 engine to rotate the final drives in the axles. This illustration shows the power train components on the 740 Articulated Dump Truck. Power flow through the power train system starts at the engine (not shown). Power then flows through the torque converter (1) into the planetary transmission (2). Power flows from the transmission through a drive shaft to the output transfer gears (3). The transfer gears divide the power flow to the front and rear axles. Power is transferred via the drive shafts (4) to the front axle (5), center axle (6), and rear axle (7). The hitch bearing (8) supports the drives shafts between the transfer gear and center axle. Power flow though the power train is the same on the 735 Trucks.
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Text Reference
68
The Transmission/Chassis ECM (arrow) is located on the right side of the cab. The ECM is an A4-M1 processor and sends signals using the Cat Data Link and the CAN Data Link. The Cat Data Link allows the Transmission/Chassis ECM to communicate with the Engine ECM, the Messenger module (if equipped), and the service port. The Transmission/Chassis ECM uses the CAN Data Link to communicate with the instrument cluster and the service port.
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Text Reference
1 6 8
7
2
5
4
3
69 At the base of the shift lever (1) is a position sensor (2) which provides input signals to the Transmission/Chassis ECM when the operator moves the lever. The shift lever position sensor is a Hall effect position sensor. The shift lever is connected to a device which contains two magnets. One magnet (3) is visible in the bottom left view. As the lever is moved, the magnets pass over the Hall Cell (4) and the change in the magnetic field produces a signal. The internal electronics (5) of the sensor process the signal and send a PWM signal to the ECM. The lever position sensor receives 24 VDC from the machine electrical system. The sensor contains a fourth pin that is used for calibration on some machine applications. The following measurements would be typical for the position sensor with the sensor connected to the Transmission/Chassis ECM and the key switch turned ON: • Pin 1 to Pin 2 -- Supply Voltage • Pin 3 to Pin 2 -- .7 - 6.9 DCV on DC volts scale • Pin 3 to Pin 2 -- 4.5 - 5.5 KHz on the KHz scale • Pin 3 to Pin 2 -- 5% - 95% duty cycle on the % scale
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Text Reference
The top gear select button (6) is used to select the desired top speed. With the engine running and the transmission control lever in the DRIVE position, pressing and holding the top gear select button will ground the Transmission/Chassis ECM top drive gear switch. The gear indicator will cycle through the available gears. When the top gear select button is released the top drive gear is set. The monitoring system will show the gear position on the display panel. When pressed, the gear hold switch (7), will ground the Transmission ECM gear hold switch. The Transmission/Chassis ECM sends a signal to the transmission solenoids, which prevents transmission shifting. This feature is used to limit the speed of the machine by not allowing the transmission to shift above the gear selected. The transmission control lever has six positions: FIRST, SECOND, THIRD, DRIVE, NEUTRAL, and REVERSE. The transmission shift lever lock button (8) unlocks the transmission shift lever when pressed. When the transmission control lever is in the DRIVE position the transmission will automatically shift between SECOND and any higher speed that is selected.
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Text Reference
735 / 740 TRANSMISSION ELECTRONIC CONTROL SYSTEM DIFFERENCES 735 SPECIFIC COMPONENTS
INPUTS
OUTPUTS Transmission Solenoids (6)
T/C Output Speed Sensor Transmission Oil Temp Sensor Transmission Filter Bypass Switch
740 SPECIFIC COMPONENTS
INPUTS
OUTPUTS Upshift Solenoid
Actual Transmission Gear Switch
Downshift Solenoid
70
The 735 transmission electronic control system components and the 740 transmission electronic control system components are similar. This illustration shows the differences between the 735 ECPC transmission input and output components and the 740 ICM transmission input and output components. The 735 transmission electronic control system components and the 740 transmission electronic control system components will be covered separately.
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Text Reference
735 CHASSIS CONTROL MODULE SYSTEM DIAGRAM 15
20 25
10
5
Messenger Module ( Opt ional SEA)
Cat Data Link
T/C Output Speed Sensor
CAN Data Link
Key Start Switch T/C Temp Sensor Retarder Lever
Transmission Output Speed Sensor
Can Data Link
Transmission Filter Bypass Switch Hoist Lever Position Sensor Shift Lever Position Sensor
Output Transfer Gear Temp Sensor Output Transfer Gear Filter Bypass Switch
Primary Steering Pressure Switch
Output Transfer Gear Pressure Switch
Park Brake Pressure Switch
Low Brake Oil Pressure Switch
Service Brake Pressure Switch Cat Data Link Park Brake Switch Inter Axle Lock Switch
Instrument Cluster
1F
132.1
Transmission Output Speed Sensor
Transmission Oil Temp Sensor
30
35
2.3
INPUTS
Engine Speed Sensor
X100 n/min
0
Front Brake Temperature Switch Rear Brake Temperature Switch Fuel Level Sender
OUTPUTS Transmission Solenoids (6)
T/C Lockup Clutch Solenoid Hoist Raise Solenoid Hoist Lower Solenoid Park Brake Solenoid Inter Axle Lock Solenoid Differential Lock Solenoid Start Relay Reverse Alarm / Lights Relay Secondary Steering Relay
Cross Axle Lock Switch Transmission Hold Switch Top Gear Limit Switch
Secondary Steering Test Switch
Hydraulic Tank Filter Bypass Switch Steer Tank Bypass Switch R - Terminal
71
735 Transmission Electronic Control System This illustration shows the 735 Articulated Dump Truck transmission/chassis electronic control system input components and output components. Input signals are provided to the Transmission/Chassis ECM from components in several machine systems. The ECM processes the input information and directs corresponding signals to the output components that are shown in the illustration. The Transmission/Chassis ECM shares signals with the Engine ECM, the instrument cluster on the CAN Data Link, and the Messenger module (if equipped) over the Cat Data Link. The main purpose of the Transmission/Chassis ECM is to determine the desired transmission gear and to energize the appropriate solenoids to shift the transmission up or down as required based on information from both the operator and machine. The Transmission/Chassis ECM controls the torque converter lockup clutch and the differential lock. The Transmission/Chassis ECM also controls all the hoist functions, the parking brake function, and other functions as described later in this presentation.
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Text Reference
3
1
2 4
7
9
5
6
8
72
This illustration shows the ECPC transmission components in the 735 truck. The torque converter lockup clutch (1) is located at the top left side of the torque converter housing. The Transmission/Chassis ECM energizes the lockup solenoid to engage the lockup clutch in the torque converter. The Transmission/Chassis ECM must receive a valid signal from one of the two transmission output speed sensors (2) and a signal from the engine output speed sensor before the lockup solenoid is energized. A pressure tap (3) is located on the lockup up clutch to check the lockup clutch pressure. The transmission output speed (TOS) sensors send a signal to the Transmission/Chassis ECM which indicates the output speed of the transmission. Based on the inputs from the TOS sensors the ECM determines when the transmission needs to be shifted. A warning is displayed on the instrument cluster when either of the output speed sensors fail. The ECM records a CID 0585 when TOS 1 fails. The ECM records a CID 0673 when TOS 2 fails. The torque converter output speed sensor (4) sends an input to the Transmission/Chassis ECM. The ECM uses the torque converter output speed sensor information to diagnose each of the other speed sensors mounted on the transmission as well as to aid in the calibration of the transmission clutches.
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Text Reference
The filter bypass valve (5) is located on the left side of the transmission case. The oil filter bypass valve allows oil to bypass the filter when the filter becomes plugged. A pressure tap (6) is used to check the inlet pressure to the transmission filter. The filter bypass switch (7) sends a signal to the Transmission/Chassis ECM when the transmission filter becomes plugged. The ECM will illuminate an indicator in the cab when the filter becomes plugged. The transmission temperature sensor (8) sends and input to the Transmission/Chassis ECM indicating transmission oil temperature. The ECM uses the input from the temperature sensor to adjust the shift times of the transmission and provide smooth shifts regardless of oil temperature. The transmission modulating valve solenoids (9) receive a signal from the Transmission/Chassis ECM to direct oil to the hydraulic clutches.
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Text Reference
73
This illustration shows the engine speed sensor (arrow) location on the 735 trucks. The engine speed sensor sends an input to the Transmission/Chassis ECM. The ECM uses the input from the sensor to calibrate the transmission solenoids and to enable/disable the lockup clutch solenoid. The ECM will log a CID 0190 when the engine speed sensor fails.
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Text Reference
74
This illustration shows the location of the torque converter oil temperature sensor (arrow) on the 735 trucks. The sensor is located on the right side of the engine, at the inlet of the transmission cooler. The temperature sensor sends a signal to the Transmission/Chassis ECM indicating torque converter oil temperature. The ECM then sends a signal to the instrument cluster where a gauge displays the temperature for the operator. The temperature can also be monitored in Cat ET. The ECM will log a CID 0826 when the temperature sensor fails.
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Text Reference
2
7
5 1
6 9
8
4 10 3
10
75 735 Transmission Hydraulic System The transmission pump (not visible) is a gear pump that is driven by the torque converter and located inside the transmission housing. The transmission pump supplies oil to the torque converter lockup clutch valve, the main relief valve, and the modulating valves. Oil from the transmission pump first flows through the transmission filter (not visible) which is located inside the filter housing (1). The filter bypass valve (2) allows cold oil to bypass the filter. The main relief valve (3) regulates the supply pressure inside the transmission hydraulic system. The relief valve is adjustable by turning the adjusting screw on the bottom of the valve. Main relief pressure can be checked at the pressure tap (4) on the main relief valve. The following pressure taps are located on the transmission: - Transmission supply system pressure (5)
- Transmission lube (9)
- Torque converter inlet pressure (6)
- Transmission modulating valves (10)
- Lockup clutch pressure (7) - Torque converter outlet/cooler inlet pressure (8)
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Text Reference
Lockup Clutch
76
This illustration of the torque converter shows the internal components. The lockup clutch allows the direct drive function and reduces power loss to a minimum. Torque converter drive is available in the first gear, the second gear, and the reverse gear. The lockup clutch provides direct drive once the transmission speed and the engine speed are matched. Direct drive is provided in all the higher gears. The lockup clutch is disengaged during transmission shifts to allow a smooth transition between gears.
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Lockup Piston
Turbine
Impeller
Text Reference
TORQUE CONVERTER CONVERTER DRIVE
Stator
Torque Converter Inlet Oil
77
Freewheel Assembly
Torque Converter Lockup Oil Passage
This sectional view shows a torque converter in CONVERTER DRIVE. The lockup clutch (yellow piston and blue disks) is not engaged. During operation, the rotating housing and impeller (red) can rotate faster than the turbine (blue). The stator (green) remains stationary and multiplies the torque transfer between the impeller and the turbine. The output shaft rotates slower than the engine crankshaft, but with increased torque. Lockup Piston
Turbine
Impeller
TORQUE CONVERTER DIRECT DRIVE
Stator
Torque Converter Inlet Oil
78
Freewheel Assembly
Torque Converter Lockup Oil Passage
In DIRECT DRIVE, the lockup clutch is engaged by hydraulic pressure and locks the turbine to the impeller. The housing, the impeller, the turbine, and the output shaft then rotate as a unit at engine rpm. The stator, which is mounted on a one-way clutch, is driven by the force of the oil in the housing. The one-way clutch permits the stator to turn freely in DIRECT DRIVE when torque multiplication is not required.
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Text Reference
735 TRANSMISSION PLANETARY
3
4
1 5 2 8
7
6
79
The planetary transmission has eight forward speeds and one reverse speed. REVERSE and NEUTRAL use only torque converter drive. At lower ground speeds, FIRST speed and SECOND speed use torque converter drive. As the ground speed increases in FIRST speed or in SECOND speed, the lockup clutch of the torque converter engages. This provides FIRST speed or SECOND speed with direct drive. The torque converter is always in direct drive for speeds THIRD through SIXTH, but there is a short period of torque converter drive when the clutches engage in the planetary transmission. This action provides smooth, automatic upshifting from THIRD through EIGHTH and smooth, automatic downshifting from EIGHTH through THIRD. The planetary transmission consists of two rotating clutches, four stationary clutches, and four planetary units, which provides eight forward speeds and one reverse speed. The No. 1 clutch (1) and the No. 2 clutch (2) are the rotating clutches. The planetary transmission is bolted to the torque converter housing. The input shaft (3) is connected to the torque converter output shaft. The output yoke (4) is bolted to the main drive shaft (not shown). The main drive shaft connects the planetary transmission with the transfer gears and case.
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The four stationary clutches are: - Clutch No. 6 (5) - Clutch No. 5 (6) - Clutch No. 4 (7) - Clutch No. 3 (8)
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Text Reference
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Text Reference
ENGAGEMENT OF TRANSMISSION CLUTCHES Transmission Speed
Engaged Clutches in the Transmission
NEUTRAL
6
REVERSE
3 and 6
FIRST speed
4 and 6
SECOND speed
1 and 6
THIRD speed
1 and 4
FOURTH speed
1 and 5
FIFTH speed
1 and 3
SIXTH speed
1 and 2
SEVENTH speed
2 and 3
EIGHTH speed
2 and 5
80
The table in this illustration lists the solenoids that are energized and the clutches that are engaged for each transmission speed. This table can be useful for transmission diagnosis.
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Text Reference
735 TRANSMISSION HYDRAULIC SYSTEM NEUTRAL
Temperature Sensor
T/C Lockup Solenoid
Bypass Switch
LUC
Torque Converter Inlet Tap
Pressure Tap
Main Relief Tap
Transmission Pump
Main Relief Valve
Screen
Transmission Sump
1
Torque Converter Outlet Relief Valve Cooler
Torque Converter Inlet Relief Valve
2
To Transmission Lubrication
3
4
6
5
6 Clutch Modulating Valves
81
The transmission pump pulls oil from the bottom of the transmission case through a magnetic screen and sends the oil through the transmission oil filter to the lockup clutch valve, the transmission main relief valve, and six clutch modulating valves. The main relief valve regulates the transmission supply pressure inside the transmission hydraulic system. Oil unseats the check ball and forces the spool to the right if the transmission system pressure becomes greater than the spring force on the right of the spool. Excess oil will flow to the transmission sump. The main relief valve is adjustable by turning the adjusting screw on the right end of the valve. The main relief valve also provides inlet oil to the torque converter. Oil seeps past the spool and flows to the inlet of the torque converter. Torque converter inlet oil will unseat the torque converter inlet relief valve and flow to the transmission sump if the torque converter inlet oil pressure becomes to high. Torque converter outlet oil pressure is limited by the torque converter outlet relief valve. Oil from the outlet of the torque converter flows through the transmission cooler and to the transmission for lubrication.
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Text Reference
The clutch modulating valves control the engagement of the transmission clutches. The solenoids are controlled by a pulse width modulated signal (PWM) from the Transmission/Chassis ECM. Supply oil flows into the clutch modulating valves and through a passage in the center of the spool. Oil then flows to the tank if the solenoid is not energized. Oil flow is blocked by a ball and seat if the solenoid is energized. The spool will shift down and the clutch will begin to fill. The signal from the Transmission/Chassis ECM determines how long it takes to fill each clutch.
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Text Reference
82
The transmission oil cooler (arrow) is located on the right side of the engine. Oil from the torque converter flows through the oil cooler and is then used to lubricate the transmission.
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Text Reference
TRANSMISSION MODULATING VALVE NO COMMANDED SIGNAL Test Port Valve Spool
Ball Orifice
Solenoid
Pin
Drain Orifice
Spring
From Pump To Tank
To Clutch
83
In this illustration, the transmission modulating valve is shown with no current signal applied to the solenoid. The Transmission/Chassis ECM controls the rate of oil flow through the transmission modulating valves to the clutches by changing the signal current strength to the solenoid. With no current signal applied to the solenoid, the transmission modulating valve is DE-ENERGIZED and oil flow to the clutch is blocked. The transmission modulating valve is located on the transmission control valve. Pump oil flows into the valve body around the valve spool and into a drilled passage in the center of the valve spool. The oil flows through the drilled passage and orifice to the left side of the valve spool to a drain orifice. Since there is no force acting on the pin assembly to hold the ball against the drain orifice, the oil flows through the spool and the drain orifice past the ball to the tank. The spring located on the right side of the spool in this view holds the valve spool to the left. The valve spool opens the passage between the clutch passage and the tank passage and blocks the passage between the clutch passage and the pump supply port. Oil flow to the clutch is blocked. Oil from the clutch drains to the tank preventing clutch engagement.
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Text Reference
TRANSMISSION MODULATING VALVE COMMANDED SIGNAL BELOW MAXIMUM Test Port Ball
Solenoid
Pin
Valve Spool
Orifice
Drain Orifice
Spring
From Pump To Tank
To Clutch
84
In this illustration, the modulating valve is shown with a signal to the solenoid that is below the maximum current. Clutch engagement begins when the Transmission/Chassis ECM sends an initial current signal to ENERGIZE the solenoid. The amount of commanded current signal is proportional to the desired pressure that is applied to the clutch during each stage of the engagement and disengagement cycle. The start of clutch engagement begins when the current signal to the solenoid creates a magnetic field around the pin. The magnetic force moves the pin against the ball in proportion to the strength of the current signal from the Transmission/Chassis ECM. The position of the ball against the orifice begins to block the drain passage of the oil flow from the left side of the valve spool to the tank. This partial restriction causes the pressure at the left end of the valve spool to increase. The oil pressure moves the valve spool to the right against the spring. As the pressure on the right side of the valve spool overrides the force of the spring, the valve spool shifts to the right. The valve spool movement starts to open a passage on the right end of the valve spool for pump supply oil to fill the clutch. Oil also begins to fill the spring chamber on on the right end of the spool.
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Text Reference
In the initial clutch filling stage, the Transmission/Chassis ECM commands a high current pulse to quickly move the valve spool to start filling the clutch. During this short period of time, the clutch piston moves to remove the clearances between the clutch discs and plates to minimize the amount of time required to fill the clutch. The ECM then reduces the current signal which reduces the pressure setting of the proportional solenoid valve. The change in current signal reduces the flow of oil to the clutch. The point where the clutch plates and discs start to touch is called TOUCH-UP. Once TOUCH-UP is obtained, the Transmission/Chassis ECM begins a controlled increase of the current signal to start the MODULATION cycle. The increase in the current signal causes the ball and pin to further restrict oil through the drain orifice to tank causing a controlled movement of the spool to the right. The spool movement allows the pressure in the clutch to increase. During the MODULATION cycle, the valve spool working with the variable commanded current signal from the Transmission/Chassis ECM acts as a variable pressure reducing valve. The sequence of partial engagement is called desired slippage. The desired slippage is controlled by the application program stored in the Transmission/Chassis ECM.
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Text Reference
TRANSMISSION MODULATING VALVE COMMANDED SIGNAL AT MAXIMUM Test Port Ball
Solenoid
Pin
Drain Orifice
Valve Spool
Orifice
To Tank
To Clutch
Spring
From Pump
85
In this illustration, the modulating valve is shown with a maximum current signal commanded to the solenoid. When the modulation cycle stops, the Transmission/Chassis ECM sends the maximum specified current signal to fully engage the clutch. The constant current signal pushes the pin firmly against the ball in the solenoid valve. The pin force against the ball blocks more oil from flowing through the drain orifice. This restriction causes an increase in pressure on the left side of the valve spool. The valve spool moves to the right to allow pump flow to fully engage the clutch. In a short period of time, maximum pressure is felt at both ends of the proportional solenoid valve spool. This pressure, along with the spring force on the right end of the spool, cause the valve spool to move to the left until the forces on the right end and the left end of the valve spool are balanced. The valve spool movement to the left (balanced) position reduces the flow of oil to the engaged clutch. The Transmission/Chassis ECM sends a constant maximum specified current signal to the solenoid to maintain the desired clutch pressure.
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Text Reference
The different maximum specified pressures for each clutch is caused by different maximum current signals being sent by the Transmission/Chassis ECM to each individual modulating valve. The different maximum signal causes a difference in the force pushing the pin against the ball to block leakage through the drain orifice in each solenoid valve. The different rate of leakage through the spool drain orifice provides different balance positions for the proportional solenoid valve spool. Changing the valve spool position changes the flow of oil to the clutch and the resulting maximum clutch pressure. The operation of the proportional solenoid to control the engaging and releasing of clutches is not a simple on and off cycle. The Transmission/Chassis ECM varies the strength of the current signal through a programmed cycle to control movement of the valve spool. The clutch pressures can be changed using Cat ET during the calibration procedure.
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Text Reference
MAIN RELIEF VALVE Torque Converter Inlet Tap
Main Relief Tap
To Torque Converter Ball Adjusting Screw
Slug
Torque Converter Inlet Relief Valve
From Pump
86
The transmission hydraulic control relief valve is used to regulate the pressure to the main components in the transmission. The transmission hydraulic control relief valve also provides oil to the torque converter. Oil enters the relief valve at the supply port. The pressure of the oil unseats the ball and moves the spool toward the right. Oil flows past the spool and to the inlet of the torque converter. The torque converter relief valve controls the inlet oil pressue in the torque converter. As the pressure of the oil to the torque converter rises, the torque converter inlet relief valve allows the oil to escape to the transmission sump. The adjustment screw alters the preload on the spring to adjust the relief pressure.
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Text Reference
740 CHASSIS CONTROL MODULE SYSTEM DIAGRAM 15
20 25
10
5
Messenger Module (Optional SEA)
Cat Data Link
Transmission Output Speed Sensor Transmission Output Speed Sensor Actual Transmission Gear Switch
CAN Data Link
Retarder Lever Can Data Link Output Transfer Gear Temp Sensor
Shift Lever Position Sensor
Output Transfer Gear Filter Bypass Switch Output Transfer Gear Pressure Switch
Park Brake Pressure Switch Service Brake Pressure Switch
Low Brake Oil Pressure Switch
Cat Data Link
Front Brake Temperature Switch
Park Brake Switch
Rear Brake Temperature Switch
Inter Axle Lock Switch Cross Axle Lock Switch
Instrument Cluster
35
OUTPUTS
Key Start Switch T/C Temp Sensor
Hoist Lever Position Sensor
Primary Steering Pressure Switch
30
1F
132.1
INPUTS Engine Speed Sensor
X100 n/min
0
2.3
Fuel Level Sender Secondary Steering Test Switch
Upshift Solenoid Downshift Solenoid
T/C Lockup Clutch Solenoid Hoist Raise Solenoid Hoist Lower Solenoid Park Brake Solenoid Inter Axle Lock Solenoid Differential Lock Solenoid Start Relay Reverse Alarm / Lights Relay Secondary Steering Relay
Transmission Hold Switch Top Gear Limit Switch Hydraulic Tank Filter Bypass Switch Steer Tank Bypass Switch R - Terminal
87
740 Transmission Electronic Control System This illustration shows the 740 Articulated Dump Truck transmission/chassis electronic control system input components and output components. Input signals are provided to the Transmission/Chassis ECM from components in several machine systems. The ECM processes the input information and directs corresponding signals to the output components that are shown in the illustration. The Transmission/Chassis ECM shares signals with the Engine ECM, the instrument cluster on the CAN Data Link, and the Messenger module (if equipped) over the Cat Data Link. The main purpose of the Transmission/Chassis ECM is to determine the desired transmission gear and to energize the appropriate solenoids to shift the transmission up or down as required based on information from both the operator and machine. The Transmission/Chassis ECM controls the torque converter lockup clutch and the differential lock. The Transmission/Chassis ECM also controls all the hoist functions, the parking brake function, and other functions as described later in this presentation.
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Text Reference
1
4
2
3
6
8
7
5
88 These illustrations show the 740 transmission components. The upshift solenoid (1), downshift solenoid (2), and lockup clutch solenoid (3) are located below a cover (4) on the right side of the transmission. The actual transmission gear switch (5), is accessed by removing a cover (6) on the right side of the transmission. The transmission output speed sensors are located on the transmission output shaft. One speed sensor (7) is visible and the other sensor is located below the cover (8). NOTE: The cover (4) is removed when the machine is shipped from the factory. The upshift and downshift solenoids are outputs of the ECM. The upshift and downshift solenoids control the oil flow that turns the rotary actuator, which shifts the transmission. The torque converter lockup clutch solenoid directs oil flow to the torque converter lockup clutch which locks the torque converter. The Transmission ECM must receive a valid signal from one of the two transmission output speed sensors and a signal from the engine output speed sensor before the lockup solenoid is energized. The gear position switch is connected to the transmission rotary actuator. The switch is a Hall-Effect type switch, which provides actual gear position input signals to the Transmission ECM.
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Text Reference
The transmission output speed sensors provide a frequency signal to the Transmission ECM indicating transmission output shaft speed. The ECM uses transmission output speed sensor information to shift the transmission.
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A B
J
C
I D
H G F
Text Reference
1
Gnd Verify
2
Gear 5
3
Gear 4
4 5 6 7 8 9 10
+ Batt Gear 3 Gear 2 Gear 1 Ground
E
TRANSMISSION GEAR POSITION SWITCH 10 9 8 7 6
4 3 2 1
89
The upshift or downshift solenoid is energized and the rotary actuator rotates until the transmission gear position switch signals the Transmission/Chassis ECM that a new gear position has been reached. Five of the six wires in the sensor provide a code to the ECM. The code is unique for each position of the transmission gear position sensor. Each transmission gear position will result in two of the five wires sending a ground signal to the ECM. The other three wires will remain open (ungrounded). The pair of grounded wires is unique for each gear position. The sixth wire is known as the "ground verify" wire, which is normally grounded. The ground verify wire is used by the ECM to verify that the transmission gear switch is connected to the Transmission ECM. The ground verify wire allows the ECM to distinguish between the loss of the transmission gear switch signals and a condition in which the transmission gear switch is between gear detent positions.
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Text Reference
90
This illustration shows the engine speed sensor (arrow) on the 740 trucks. The engine speed sensor sends an input to the Transmission/Chassis ECM. The ECM uses the input from the sensor to calibrate the transmission solenoids and to enable/disable the lockup clutch solenoid. The ECM will log a CID 0190 when the engine speed sensor fails.
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Text Reference
91
This illustration shows the location of the torque converter oil temperature sensor (arrow) on the 740 trucks. The sensor is located on the right side of the engine, at the inlet of the transmission cooler. The temperature sensor sends s signal to the Transmission/Chassis ECM indicating torque converter oil temperature. The ECM then sends a signal to the instrument cluster where a gauge displays the temperature for the operator. The temperature can also be monitored in Cat ET. The ECM will log a CID 0826 when the temperature sensor fails.
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Text Reference
1 3 2
2 7
6
5 4
92 740 Transmission Hydraulic System The transmission pump (1) is a gear pump that is driven by the torque converter via an idler gear. The transmission pump is located on the top of the torque converter housing. The transmission pump supplies oil through the transmission oil filter (2) to the hydraulic control valve (bottom left illustration) on top of the transmission. The transmission oil filter is located on the right side of the engine and contains a bypass relief valve and an S•O•S tap (3) in the base of the oil filter. Oil flows from the transmission oil filter to the transmission hydraulic control valve. The oil is used to shift the transmission and fill the clutches. Some of the oil flows to the bottom of the housing to be scavenged, but most of the oil flows to the torque converter through the outlet hose to provide oil for the torque converter. The main components in the hydraulic control valve are the rotary actuator (4), pressure control valve (5), and selector and pressure control valve (6). The transmission pressure relief valve is part of the transmission hydraulic control valve. The relief valve limits the maximum pressure in the transmission charging circuit. Transmission clutch pressures are tested at the pressure taps on top of the hydraulic control valve. The pressure taps can be accessed by removing a cover plate on top of the transmission.
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Text Reference
The transmission oil cooler (7) is located on the right side of the engine. Oil from the torque converter flows through the oil cooler and is then used to lubricate the transmission, the pump drive group, and the accessory drive group.
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Text Reference
4 2
1
3
10
7
9 5
6
8
93 Also located on the transmission hydraulic control valve is the lockup clutch modulating valve (1). The top left illustration shows the hydraulic control valve with the lockup clutch modulating valve removed. The following pressure taps or plugs are located on the transmission: - Transmission individual clutch pressures (2) - Pilot pressure (3) - Lockup clutch pressure (4) - Lockup clutch pilot pressure (5) - Main relief pressure (6) - Upshift solenoid pressure (7) - Downshift solenoid pressure (8) - Lube pressure (9) - Inlet relief valve pressure (10) - remove line and and install tap
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Text Reference
2
1
3 740 TORQUE CONVERTER
7
5 8
4
6
94 This illustration of the torque converter shows the following internal components: - Housing (1)
- One-way clutch (5)
- Turbine (2)
- Impeller (6)
- Stator (3)
- Hub (7)
- Shaft (4) The lockup clutch (8) allows the direct drive function and reduces power loss to a minimum. Torque converter drive is available in first gear and reverse gear. The lockup clutch provides direct drive once the transmission speed and the engine speed are matched. Direct drive is provided in all the higher gears. The lockup clutch is disengaged during transmission shifts to allow a smooth transition between gears.
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Lockup Piston
Turbine
Impeller
Text Reference
TORQUE CONVERTER CONVERTER DRIVE
Stator
Torque Converter Inlet Oil
95
Freewheel Assembly
Torque Converter Lockup Oil Passage
This sectional view shows a torque converter in CONVERTER DRIVE. The lockup clutch (yellow piston and blue disks) is not engaged. During operation, the rotating housing and impeller (red) can rotate faster than the turbine (blue). The stator (green) remains stationary and multiplies the torque transfer between the impeller and the turbine. The output shaft rotates slower than the engine crankshaft, but with increased torque. Lockup Piston
Turbine
Impeller
TORQUE CONVERTER DIRECT DRIVE
Stator
Torque Converter Inlet Oil
96
Freewheel Assembly
Torque Converter Lockup Oil Passage
In DIRECT DRIVE, the lockup clutch is engaged by hydraulic pressure and locks the turbine to the impeller. The housing, impeller, turbine, and output shaft then rotate as a unit at engine rpm. The stator, which is mounted on a one-way clutch, is driven by the force of the oil in the housing. The one-way clutch permits the stator to turn freely in DIRECT DRIVE when torque multiplication is not required.
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Text Reference
740 TRANSMISSION PLANETARY 5
6
8 1
2
7
9
4 3
97
The planetary transmission has seven forward speeds and two reverse speeds. REVERSE and NEUTRAL use only torque converter drive. At lower ground speeds, FIRST speed uses torque converter drive. As the ground speed increases in FIRST speed, the lockup clutch of the torque converter engages. This provides FIRST speed with direct drive. The torque converter is always in direct drive for speeds SECOND through SEVENTH, but there is a short period of torque converter drive when the clutches engage in the planetary transmission. This provides smooth, automatic upshifting from SECOND through SEVENTH and smooth, automatic downshifting from SEVENTH through SECOND. The planetary transmission consists of two rotating clutches, five stationary clutches, and five planetary units, which provides eight forward speeds and two reverse speeds. The No. 3 clutch (1) and the No. 4 clutch (2) are the rotating clutches. The planetary transmission is bolted to the torque converter housing. The input shaft (3) is connected to the torque converter output shaft. The output yoke (4) is bolted to the main drive shaft (not shown). The main drive shaft connects the planetary transmission with the transfer gears and case.
SERV1838 06/07
The five stationary clutches are: - Clutch No. 1 (5) - Clutch No. 2 (6) - Clutch No. 5 (7) - Clutch No. 6 (8) - Clutch No. 7 (9)
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Text Reference
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Text Reference
ENGAGEMENT OF TRANSMISSION CLUTCHES Transmission Speed
Engaged Clutches in the Transmission
NEUTRAL
1
FIRST REVERSE speed
1 and 7
SECOND REVERSE speed
3 and 7
FIRST speed
2 and 6
SECOND speed
1 and 6
THIRD speed
3 and 6
FOURTH speed
1 and 5
FIFTH speed
3 and 5
SIXTH speed
1 and 4
SEVENTH speed
3 and 4
98
The table in this illustration lists the solenoids that are energized and the clutches that are engaged for each transmission speed. This table can be useful for transmission diagnosis.
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Text Reference
2
1
99
The 740 trucks now have a modified transmission arrangement, which provides a second reverse gear to enhance performance when operating in long rear hauling applications typical of larger machines. The additional (second reverse) gear provides a 10% increase in rimpull over first reverse gear. Additional rimpull provides better traction on wet or steep grades and in slippery terrain. To select 1st gear reverse, move the transmission lever to reverse (1). To upshift from first gear reverse to second gear reverse, press the transmission hold switch (2). When ground speed is approximately 8 km/h (5 mph) the transmission will automatically upshift. If ground speed decreases to the shift point rpm, the transmission will automatically downshift to first gear reverse. The transmission hold switch must be pressed every time if second gear reverse is required.
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Text Reference
TRANSMISSION HYDRAULIC SYSTEM NEUTRAL
Oil Filter
Downshift Upshift Solenoid Solenoid
Downshift Pressure
3
Upshift Pressure
A
Rotary Actuator
1
Pump Pressure
B
E 5
Neutralizer Valve Pilot Oil Pressure
Priority Reduction Valve
2
Rotary Selector Spool
C
F 4
Transmission Pump
G 6 D
Relief Valve
Lockup Clutch Valve To Torque Converter Inlet
Selector Valve Group
From Lockup Clutch Valve Solenoid
H 7 Pressure Control Group
Torque Converter Inlet Relief Valve
100
This schematic shows the conditions in the system with the engine running and the transmission in NEUTRAL. The priority reduction valve has two functions: First, it controls the pressure of the pilot oil (orange) that is used to initiate clutch engagement; second, it makes sure that pilot pressure is available at the neutralizer valve before pressure oil (red) is sent to the remainder of the system. The neutralizer valve moves only when the rotary selector spool is in the NEUTRAL position. When the rotary selector spool is in the NEUTRAL position and the engine is started, pump oil flows through a passage in the center of the neutralizer valve, flows up around the check ball, pressurizes the top of the valve, and then moves down. In this position, the neutralizer valve directs pilot oil to the center of the rotary selector spool. If the rotary selector spool is not in the NEUTRAL position during engine start-up, the neutralizer valve will block the flow of pilot oil to the rotary selector spool. Directly below the neutralizer valve is the main relief valve. This valve limits the maximum system pressure. Excess pump oil is directed to the torque converter and the pressure is maintained by the torque converter inlet relief valve.
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Text Reference
To initiate a shift, pressure oil from either the upshift or downshift solenoid is sent to the rotary actuator. Inside the actuator housing is a rotating vane which divides the actuator into two chambers. Pressure oil from the upshift solenoid causes the vane to rotate in one direction while pressure oil from the downshift solenoid causes the vane to rotate in the opposite direction. The vane is connected to and causes rotation of the rotary selector spool inside the selector valve group. From the transmission pump, oil flows through the filter and is sent directly to the two solenoids and the selector valve group. Pump flow is blocked at the upshift solenoid and, because the downshift solenoid is continuously energized in NEUTRAL, the valve in the solenoid is open. This condition permits oil to flow to the rotary actuator. Pressure on the downshift side of the rotating vane in the rotary actuator keeps the vane and the rotary selector spool in the NEUTRAL position until a shift is made. The rotary selector spool is actually a hollow rotating shaft. A plug and screen assembly inside the spool divides the center cavity into two separate oil chambers. During operation, pilot oil from the upper chamber is directed to the pressure control valve group to initiate clutch engagement. For any gear except NEUTRAL, two of the outlet ports from the upper chamber are aligned with drilled passages in the selector valve body. For NEUTRAL, only one outlet port permits pilot oil to flow to the pressure control valve group. The lower chamber in the rotary selector spool is always open to drain. For each gear position except NEUTRAL, all but two of the drain ports are open to drain. Whenever a clutch station is engaged, the lower half of the spool blocks the drain passage to that station. All oil that is in the bottom of the transmission case is returned to the differential case by the transmission scavenge section of the transmission pump.
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Text Reference
TRANSMISSION HYDRAULIC SYSTEM DOWNSHIFTING TO NEUTRAL
Downshift Solenoid
Upshift Solenoid Drain Passage 5
4
6
3
Shuttle Valve
7
Shuttle Valve
2 1 R From Pump
Rotary Actuator
1
R 2
N
Rotary Stationary Drain Vane Vane Passage
101
The rotary actuator is controlled by the downshift solenoid and the upshift solenoid. Pressurized oil from either solenoid flows into the chamber of the rotary actuator. The pressurized oil will push against the stationary vane and rotary vane. The pressurized oil will cause the rotary valve to rotate one direction or the other. The rotary vane is mechanically connected to the rotary selector spool. The rotary vane turns the rotary selector spool whenever the rotary vane moves. The downshift solenoid is energized during a downshift. Pressurized oil flows from the downshift solenoid to the rotary actuator. The pressurized oil pushes the shuttle valve to the left. The ball inside the shuttle valve is pushed open by pressurized oil once the shuttle valve has moved all the way to the left. The shuttle valve blocks the drain passage and pressurized oil now fills the rotary actuator and begins to move the rotary vane counterclockwise. As the rotary vane moves counterclockwise, it forces oil out the opposite side of the rotary actuator. This oil forces the other shuttle valve to the right. A passage is open to drain when the shuttle valve has moved all the way to the right. Oil on the right side of the rotary vane is open to drain and the rotary vane begins to move counterclockwise.
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Text Reference
SELECTOR VALVE GROUP NEUTRAL
Pilot Oil Pressure
Priority Neutralizer Reduction Valve Valve
Rotary Selector Spool
Relief Valve
To Torque Converter Inlet
Torque Converter Inlet Relief Valve
Selector Valve Group
102
As pressurized oil enters the selector valve it flows upward past the priority reduction valve and charges the pilot circuit. When the pilot circuit reaches the proper pressure, oil opens the check valve at the top of the priority reduction valve. Oil fills the cavity above the priority reduction valve and forces the valve downward against the force of the spring which blocks the flow of oil to the pilot circuit. This valve will meter open and closed to maintain the pressure in the pilot circuit. As the neutralizer valve moves downward, pilot oil is able to flow through an orifice in the neutralizer valve to the chamber above the neutralizer valve. The neutralizer valve will now be held open by the pilot oil until the machine is turned off. Once the neutralizer valve has shifted downward, a passage is open for the pilot oil to flow to the rotary selector spool. The rotary selector spool directs pilot oil to the appropriate clutch station to initiate a shift. The upper end of the rotary selector spool is attached to the rotary actuator and the transmission gear position switch. The Transmission/Chassis ECM uses the transmission gear position switch to determine which gear the transmission is in.
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Text Reference
There is a cam and spring assemble connected to the lower end of the rotary selector spool. The cam and springs provide detent positions in order to hold the spool in each selected speed position. The relief valve controls the maximum pressure in the transmission hydraulic system. Oil flows through an orifice in the relief. This opens a poppet valve. Oil fills the chamber between the poppet and the slug. As the pressure increases, the oil moves the relief valve upward against the force of the spring. When the pressure of the oil reaches the relief pressure, the relief valve allows oil to flow out to the torque converter. The torque converter inlet relief valve controls the maximum oil pressure that is going into the torque converter. The torque converter inlet relief valve will open if the inlet pressure of the torque converter oil reaches the relief setting of the inlet relief valve. The oil that is bypassed by the inlet relief valve will flow to the transmission case reservoir.
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Text Reference
PRESSURE CONTROL VALVE NEUTRAL
From Selector Spool
3 A
E
1 5
B
F
2 4
G 6 H
From Transmission Charging Pump
From Lockup Clutch Solenoid
7
103
This illustration shows the pressure control group which is located above the selector valve group. The pressure control group is made up of seven modulating reducing valves, one reducing valve for each clutch. The reducing valves are referred to as "valve stations." Each valve station controls the primary pressure, modulation of engagement time, maximum pressure and release "decay time" for a particular clutch. Each valve station is identified by a letter stamped on the control valve cover (A, B, C, E, F, G, and H). Notice that each station letter corresponds with the number of the clutch that is controlled by that valve station. For example, the A station controls clutch No. 3, the B station controls clutch No. 1, and the C station controls the clutch No. 2. NOTE: The D station controls the lockup clutch.
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Text Reference
VALVE STATION Slug
Ball Check Valve
CLUTCH RELEASED Load Piston
Selector Piston
Pilot Oil Passage
Plug Return Spring
Decay Orifice (Optional) Drain
Modulation Reduction Valve
Drain
Clutch Supply Rail
To Clutch
Load Piston Orifice
Load Piston Plug
Clutch Pressure Tap
104
Since all seven valve stations contain the same basic components, an explanation of the operation of one station can be applied to the operation of the remaining six stations. The seven stations that control the clutches contain load piston orifices (sometimes called "cascade" orifices). The load piston orifices control the clutch modulation. The thicker the orifice, the slower the modulation. The retaining springs for the load piston orifices are identical, but the orifices vary in thickness from one station to another. Many of the stations are equipped with decay orifices. Check the parts book for proper component placement. In this schematic, the engine has been started, but the clutch for this station has not been engaged. While the engine is running, pump (or system) pressure is always available at the modulation reduction valve spool; but, until pilot oil from the rotary selector spool is sent to the right (outer) end of the selector piston, there can be no valve movement and the clutch cannot be engaged.
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Text Reference
VALVE STATION Slug
Ball Check Valve
CLUTCH FILLING Load Piston
Selector Piston
Pilot Oil Passage
Plug Return Spring
Decay Orifice (Optional) Drain
Modulation Reduction Valve
Drain
Clutch Supply Rail
To Clutch
Load Piston Orifice
Load Piston Plug
Clutch Pressure Tap
105
To begin a clutch shift, the rotary selector spool directs pilot oil to the appropriate clutch stations. Valve movement is initiated when pilot oil from the rotary selector spool moves the selector piston to the left. The selector piston and load piston move together. Movement of the selector piston accomplishes two purposes: 1. The drain passage at the decay orifice is blocked. 2. The load piston springs are compressed. Compressing the load piston springs moves the modulation reduction valve spool to the left against the force of the return spring. This movement opens the supply passage and permits pressurized oil to flow to the clutch. As the clutch fills, pressurized oil opens the ball check valve and fills the slug chamber at the left end of the modulation reduction valve spool. At the same time, oil flows through the load piston orifice and fills the chamber between the end of the load piston and the selector piston. While the clutch is filling, the pressure in the chamber between the end of the load piston and the selector piston is not high enough to move the load piston inside the selector piston.
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Text Reference
After the clutch fills, the pressure in the clutch, in the slug chamber, and in the passage to the load piston orifice starts to increase. The clutch pressure and the pressure in the slug chamber increase at the same rate. Just after the clutch is filled, the pressure in the slug chamber moves the reduction valve to the right. This movement restricts the flow of pressure oil to the clutch and briefly limits the increase of clutch pressure. The pressure in the load piston chamber then moves the load piston farther to the left. This movement increases the spring force and reopens the supply passage permitting the clutch pressure to again increase. This cycle continues until the load piston has moved completely to the left (against the stop). The clutch pressure is then at its maximum setting. During modulation, the reduction valve spool moves left and right while the load piston moves smoothly to the left.
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Text Reference
VALVE STATION Slug
Ball Check Valve
CLUTCH ENGAGED Load Piston
Selector Piston
Pilot Oil Passage
Plug Return Spring
Decay Orifice (Optional) Drain
Modulation Clutch Reduction Supply Valve Rail
Drain
To Clutch
Load Piston Orifice
Load Piston Plug
Clutch Pressure Tap
106
At the end of the modulation cycle, the modulation reduction valve controls clutch pressure, which will be lower than the pump charging pressure. The pressure in the slug chamber moves the reduction valve a small distance to the right to restrict the flow of supply oil to the clutch. This is the "metering position" of the reduction valve spool. In this position, the modulation reduction valve maintains precise control of the clutch pressure. During operation, an engaged clutch is designed to leak a relatively small but steady volume of oil. As clutch leakage occurs, the clutch pressure and the pressure of the oil in the slug chamber will start to decrease. At this point, the load piston springs move the reduction valve spool a small distance to the left to open the supply passage. Pressure oil from the pump again enters the clutch circuit and replaces the leakage. Then, the clutch pressure in the slug chamber moves the spool back to the right thereby restricting the flow of supply oil to the clutch. This metering action continues during the entire time that the clutch is engaged.
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Text Reference
VALVE STATION CLUTCH DECAY
Slug
Ball Check Valve
Load Piston
Selector Piston
Pilot Oil Passage
Plug Return Spring
Decay Orifice (optional) Drain
Modulation Reduction Valve
Drain
Clutch Supply Rail
To Clutch
Load Piston Orifice
Load Piston Plug
Clutch Pressure Tap
107
During a shift, the pressure of the clutch (or clutches) being released does not immediately drop to zero. Instead, the clutch pressure decreases at a controlled rate. Restricting the rate of clutch pressure decay helps to maintain a positive torque at the transmission output shaft. This feature minimizes the effects of tire and axle "unwinding" and permits smoother shifts. An immediate drop in clutch pressure would permit a rapid deceleration of the power train components that remain connected to the differential during a shift. When a clutch is released, the chamber at the right (outer) end of the selector piston is opened to drain through the lower chamber in the rotary selector spool. This condition permits the selector piston and load piston to move to the right as shown. Clutch pressure starts to decrease, but cannot drop to zero until the chamber between the load piston and the selector piston is drained. The only way that oil can flow out of this chamber is through the decay orifice which was uncovered when the selector piston moved to the right. As the load piston springs force the oil from the load piston chamber, the clutch pressure gradually decreases. When the load piston has moved completely to the right, the clutch pressure is zero.
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Text Reference
SHIFT CYCLE
Clutch Pressure (psi) Transmission Clutch Slip
Converter Clutch Slip
400
Transmission Clutch Final Pressure
300 200
Lockup Clutch Final Pressure
Clutch 1 Primary Pressure
100
Lockup Clutch Primary Pressure Lockup Clutch Fill Pressure and Time
0 0
0.5
1.0 Clutch 1 Fill Pressure And Time Clutch 2
1.5
2.0
Clutch 1
2.5
Clutch 6
3.0
3.5
Time (second)
Lockup Clutch
108
This graph shows the clutch pressures as the ground speed increases and the transmission shifts from FIRST to SECOND gear. The lockup clutch and clutch 2 are gradually released by the controlling effects of the decay orifices. Clutch 1 fills and then the load piston orifice controls the modulation of engagement. After clutch 1 has filled, the lockup clutch solenoid is energized. The lockup clutch fills and modulates to final pressure. There is some overlap between the decay of the clutch being released and the clutch being engaged. This feature helps to minimize the unwinding motion of the power train and provides smooth shifts. Initial clutch engagement is the point where the operator can feel the transmission engaging a gear (primary pressure). Complete clutch engagement is the point where the clutch stops slipping and the transmission is fully engaged. Clutch pressures continue higher to ensure that the clutches do not slip. Clutch slip is the time between initial clutch engagement (primary pressure) and complete clutch engagement.
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Text Reference
CLUTCH FILL AND MODULATION PROBLEMS Clutch Pressure
Clutch Maximum Pressure
High Primary Pressure Harsh Shift
Final Clutch Engagement
Initial Clutch Engagement (Primary Pressure)
Slow Modulation Excessive Slip
Short Fill
Low Primary Pressure Excessive Slip
Time
Long Fill Normal
Low Primary Pressure
High Primary Pressure
Slow Modulation
109
This graph shows the effects of the following conditions: 1. High primary pressure - Shorter fill and engagement times, which cause harsh shifts. 2. Low primary pressure - Longer fill and engagement times, which cause the plates and discs to slip more before the engagement pressure holds them together. Maximum clutch pressure might be lower and may cause slippage during conditions of heavy loading. 3. Slow modulation - This also causes more slip, similar to the low primary pressure. It can be caused by a partially plugged load piston orifice or by wear in the valve station body, load piston, or selector piston.
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Text Reference
2 1
3
4
5
110
Differential System The output transfer gear (1) is used to divide the torque between the front and rear axles. The output transfer gear contains an inter-axle differential and transfer gears. The cross axle differential solenoid (2) will engage the cross axle differentials when energized. The interaxle differential solenoid (3) will engage the interaxle differential when energized. A relief valve (4) protects the differential lock system from high pressures. The yoke assembly (5) provides output drive torque to the front axle. The drive for the rear axles is not shown.
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Text Reference
111
The interaxle differential (arrow) divides the torque between the tractor and the trailer. 40% of the torque is directed to the front axle and 60% of the torque is directed to the rear axles.
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Text Reference
1
112 2
3
3
113
Power flow through the interaxle differential starts at the input shaft (1). The input shaft (1) is splined to the interaxle case (2). The planet carriers (3) are pinned to the interaxle differential case (2).
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Text Reference
3
4
114
5
3 6
115
7
The planet gears (4) will spin clockwise as the planet carrier (3) drives the planet gears. The sun gear (5) will spin counterclockwise. The sun gear (5) is splined to a shaft which directs torque to the front axle. The planet gears (6) will spin clockwise as the planet carrier (3) drives the planet gears. The sun gear (7) will spin counterclockwise. The sun gear (7) is splined to a shaft which directs torque to the rear axles.
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Text Reference
1
2
116
The yellow gears (1) transmit the torque to the front axle. The blue gears (2) transmit torque to the rear axles.
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Text Reference
1
2
117
A differential lockup clutch is used to lock up the inter-axle differential when ground conditions are poor. When the interaxle differential lockup solenoid is energized, the solenoid directs oil to the inter-axle differential piston through the port (1). The piston pushes against the plates (2) and locks the differential. As a result, the front and rear drive shafts and the differential rotate as one unit. In this condition, torque to the front and rear axles is equal. When the differential lock switch in the cab is released, the differential lockup solenoid is de-energized. The differential will unlock. The oil released from the plates is directed to the transmission sump. When the differential unlocks, the front and rear wheels can turn at different speeds.
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Text Reference
1
2
3
6
4 7
118
5
119
8
9
10
The solenoid and relief valve (1) controls the lubrication oil for the output transfer gears. The valve is located on the left side of the machine and is attached directly to the output transfer gear box. The following is a list of the components in the upper illustration. - Cross-axle solenoid valve (2) - Inter-axle solenoid valve (3) - Diverter Valve (4)
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Text Reference
- Plug to remove the orifice (5) - Oil supply hose (6) - Hose to control activation of the cross-axle clutches (7) The following is a list of the components in the lower illustration - Orifice (8) - Relief valve (9) - Hose to the remote test port panel (10) NOTE: The test port for the differential pressure tap is in the top row on the far right looking at the remote diagnostic test port panel.
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Text Reference
5
2
3 1
4
120
The output transfer gear oil filter (1) is located behind the cover on the left rear of the frame. The oil filter base is equipped with a differential pressure switch (2) and a pressure switch (3). The differential pressure switch sends a signal to the Transmission/Chassis ECM that the filter is restricted. The differential pressure switch will open if the pressure in the filter becomes to high. The Transmission/Chassis ECM will send a signal to the monitoring system which turns on the machine filter warning lamp. The pressure switch is also an input to the Transmission/Chassis ECM. The pressure switch is located in the output transfer gear filter housing. The ECM determines if the pressure for the output transfer gear is low. When the oil pressure to the differential locks is low, the switch opens. The OTG low-pressure alarm is de-activated when the OTG pressure is reported to be above 113 kPa (16 psi) The OTG low pressure alarm is activated when the all of the following are true: OTG Pressure is low, below 70 +/- 20 kPa (10 +/- 3 psi) OTG Temperature is normal, above 38° C (100° F) Engine speed is greater than 1500 rpm Also shown is the S•O•S tap (4) for the output transfer gear oil and the remote test tap panel (5). NOTE: Not all remote pressure taps may be connected.
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Text Reference
1
2
121
The OTG temperature sensor (1) is located between the output transfer gear and the transmission behind the hoist control valve (2). The temperature sensor sends an input to the Transmission/Chassis ECM monitoring the oil temperature being drawn from the output transfer gear sump. The following is a list of the diagnostic codes for the OTG temperature sensor. CID2707-FMI 03 Voltage above normal CID2707-FMI 05 Current above normal CID2707-FMI 06 Current below normal The Operator will be alerted with a level 2S warning if the temperature reaches 108º C (226° F). The temperature is also an input into activation of the OTG oil pressure warning. With the engine running and the temperature reaches 108º C a level 2S warning will be logged. When the temperature has lowered to 100º C, the warning will be cleared . The OTG oil temperature status will be indicated as LOW until the sensor reports a temperature equal to or greater than 38 ± 3º C (100 ± 0.5° F). The OTG oil temperature status is then set to normal. If the OTG oil temperature subsequently lowers below 27º C (80° F), the status will be indicated as Low.
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Text Reference
DIFFERENTIAL LOCK SYSTEM
Inter-axle Solenoid
Cross-axle Solenoid
INTER-AXLE OFF
Differential Lock Control Valve Remote Pressure Tap
Diverter Valve
Oil Cooler
Orifice Output Transfer Gear Sump
Relief Valve Pressure Tap Gear Pump
Front Axle
Center Axle
Pressure Switch Filter Differential Pressure Switch
Transfer Gears
Temperature Sensor
Rear Axle
122
When the inter-axle differential lock switch (located in the cab on the left side of the seat) is not activated, the inter-axle solenoid is de-energized. Supply oil is blocked at the inter-axle solenoid valve. The inter-axle differential lock clutch is released.
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Text Reference
DIFFERENTIAL LOCK SYSTEM
Inter-axle Solenoid
Cross-axle Solenoid
INTER-AXLE ON
Differential Lock Control Valve Remote Pressure Tap
Diverter Valve
Oil Cooler
Orifice Output Transfer Gear Sump
Relief Valve Pressure Tap Gear Pump
Front Axle
Center Axle
Pressure Switch Filter Differential Pressure Switch
Transfer Gears
Temperature Sensor
Rear Axle
123
When the operator depresses the inter-axle differential lock switch, the inter-axle solenoid is energized. Supply oil travels across the inter-axle solenoid valve and shifts the diverter valve downward, blocking flow through the diverter valve. Supply oil then flows to the inter-axle differential lock and engages the clutch. When the clutch is fully engaged, excess oil is then metered through the orifice and flows back to the output transfer gear for lubrication. NOTE: Engaging the interaxle differential lock neutralizes the differential effect between the front and rear axles.
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Text Reference
DIFFERENTIAL LOCK SYSTEM
Inter-axle Solenoid
Cross-axle Solenoid
INTER-AXLE AND CROSS-AXLE ON Differential Lock Control Valve Remote Pressure Tap
Diverter Valve
Oil Cooler
Orifice Output Transfer Gear Sump
Relief Valve Pressure Tap Gear Pump
Front Axle
Center Axle
Pressure Switch Filter Differential Pressure Switch
Transfer Gears
Temperature Sensor
Rear Axle
124
Oil flow from the previous slide shows the oil flow through the inter-axle solenoid valve and blocked at the cross-axle solenoid valve. When the inter-axle solenoid valve is energized and the operator depresses the cross-axle switch (in the cab on the dash), the cross-axle solenoid is energized and the valve is shifted upward. The oil is directed to the front axle, the center axle, and the rear axle differentials. The three axles are driving the six wheels at the same time. NOTE: The circuit allows the axle differential locks to be engaged only when the interaxle solenoid valve has already been engaged. When the ground speed exceeds 16 km/h (10 mph), the cross-axle solenoid will be de-energized by the Transmission/Chassis ECM. This will not be canceled until the machine speeds drop below 10 km/h (6 mph) and the differential lock switch (in the cab) is moved to the OFF position. While the ECM automatically kicks out the cross-axle lock, the system does not automatically restore the cross-axle until the operator’s command matches the kicked out value.
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Text Reference
1
2
3
2
125 STEERING SYSTEM The 735/740 trucks use a load sensing, pressure compensated steering system. Minimal horsepower is used by the steering system when the truck is traveling in a straight path. Steering hydraulic horsepower requirements depend on the amount of steering pressure and flow required by the steering cylinders. These illustrations show some of the main components in the steering system: - HMU (1) - Steering cylinders (2) - Steering and fan hydraulic tank (3)
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Text Reference
3
1 126
3
127 2
The steering pump is a variable displacement piston pump and is located under the cab on the right side of the machine. The top illustration shows the steering pump (1) on the 735 truck and the bottom illustration shows the steering pump (2) on the 740 truck. The pump control valve (3) contains a flow compensator spool and and a pressure compensator spool.
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Text Reference
4 3 128 1
2
5 6
129
The hydraulic tank (1) is located on the right side of the machine near the cab. The hydraulic tank holds oil for the steering and fan hydraulic systems. The hydraulic tank contains a return filter that is accessed by removing a cover (2). Also located on the top of the tank is the tank breather (3) and fill cap (4). The oil level sight gauge (not visible) is located on the right side of the machine in front of the right tire. The bottom illustration shows the steering check and combiner valve (5), which is mounted to the left side of the steering and fan hydraulic tank. The steering check and combiner valve includes two check valves that block oil flow from the primary steering pump into the secondary steering pump circuit and also block oil flow from the secondary steering pump into the primary steering pump circuit.
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Text Reference
A pressure switch (6) on the steering check and combiner valve is used to monitor the status of the primary steering system pressure. When primary steering pressure is too low, the pressure switch sends a signal to the Transmission/Chassis ECM. The Transmission/Chassis ECM will activate the secondary steering relay, which activates the secondary steering pump.
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Text Reference
130
The Hand Metering Unit (HMU) (arrow) is mounted to the front of the cab. The metering unit meters oil from the steering pump to the steering cylinders. The volume of oil that is metered to the steering cylinders depends on the rotational speed of the steering wheel. The metering unit contains two crossover relief valves to dampen the shock on the steering cylinders. The crossover relief valves are not adjustable.
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Text Reference
131
The steering cylinders are located at the oscillating hitch between the front and rear frames. This illustration shows the right steering cylinder (arrow). The head end of the cylinder is connected to the truck and the rod end of the cylinder is connected to the trailer.
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Text Reference
STEERING SYSTEM HOLD
Steering Pressure Switch
Tractor
Margin Spool
Steering Combiner Manifold
Crossover Relief Valves
Steering Cylinders Trailer
HMU Steering Pump
Secondary Steering Pump
Cutoff Spool Transmission Pump Drive
Steering Pump M
Steering And Fan Hydraulic Tank
132 This illustration shows the steering hydraulic system in the HOLD position. Oil from the steering pump flows through the check valve in the steering check and combiner valve and to the HMU. A second check valve in the steering check and combiner valve blocks oil from flowing to the secondary steering pump. In the HOLD position, the spool in the HMU blocks the steering pump oil from flowing to the steering cylinders. Steering supply oil also flows into a steering signal network through an orifice and the load sense check valve. Oil flows to the HMU and the margin spool in the pump control valve. Signal oil plus the force of the margin spring will determine the pump output. Signal oil is continually metered through the HMU to the tank in the HOLD position. Steering signal network oil is metered to the tank to keep the pump slightly upstroked in the low pressure standby condition. The slightly upstroked pump ensures a rapid response to a steering input. Signal oil from the HMU flows back to the hydraulic tank through the tank return check valve. The tank return check valve maintains a slight back pressure in the signal network. Maintaining the back pressure will ensure a rapid response from the HMU to a steering input.
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Text Reference
STEERING SYSTEM RIGHT TURN
Steering Pressure Switch Steering Cylinders
Steering Combiner Manifold
Crossover Relief Valves HMU Steering Pump
Flow Compensator Spool Secondary Steering Pump
Cutoff Spool Transmission Pump Drive
Steering Pump M
Steering and Fan Hydraulic Tank
133
This schematic shows the steering system in a RIGHT TURN position. The steering pump supplies oil to the HMU. The gerotor pump in the HMU rotates with the steering wheel as the operator makes a turn. The gerotor pump transfers oil to the steering cylinders as the pump rotates. Return oil flows from the steering cylinders to the hydraulic tank. The HMU has an internal crossover valve and an internal check valve for each steering cylinder. The crossover valves and check valves will direct oil from one side of the steering circuit to the other in the event of a pressure spike. Load sensing pressure is transmitted to the load sensing line through an orifice in the directional spool of the HMU. The load sensing pressure is proportional to the rotational speed of the steering wheel and the resistance to turn the machine. The load sensing pressure causes the output of the piston pump to increase to match the requirements of the steering system.
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Text Reference
2
1
134
Secondary Steering System The secondary steering pump (1) is located on the right side of the machine next to the engine and is driven by an electric motor (2). The secondary steering system has three states: - OFF - Armed - ON The secondary steering system will be OFF after the machine is powered up. The Transmission/Chassis ECM will arm the secondary steering system whenever engine speed is over 500 rpm or machine speed is over 8 km/h (5 mph). The Transmission/Chassis ECM will activate the secondary steering relay, which turns on the pump, only after the system is armed and the ECM has detected the loss of primary steering pressure. The Transmission/Chassis ECM will log a level 3 event and turn on the secondary steering system if the primary steering pressure falls below 700 kPa (100 psi).
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Text Reference
STEERING SYSTEM
SECONDARY STEERING - HOLD Steering Pressure Switch
Tractor
Margin Spool
Steering Combiner Manifold
Crossover Relief Valves
Steering Cylinders Trailer
HMU Steering Pump
Secondary Steering Pump
Cutoff Spool Transmission Pump Drive
Steering Pump M
Steering And Fan Hydraulic Tank
135
The secondary steering electric drive pump supplies oil to the HMU in the event of a loss in primary steering pressure. Oil flows from the secondary steering pump through a directional control valve in the pump and a check valve in the steering check and combiner valve to the HMU. A second check valve in the steering check and combiner valve blocks oil from flowing to the primary steering pump. In the HOLD position, the spool in the HMU blocks the secondary steering pump oil from flowing to the steering cylinders.
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Text Reference
STEERING SYSTEM RIGHT TURN USING SECONDARY STEERING
Steering Pressure Switch Steering Cylinders
Steering Combiner Manifold
Flow Compensator Spool
Crossover Relief Valves
HMU Steering Pump
Secondary Steering Pump
Cutoff Spool Transmission Pump Drive
Steering Pump M
Steering and Fan Hydraulic Tank
136
This illustration shows the steering system in a right turn position with the secondary steering pump activated. The gerotor pump in the HMU transfers secondary supply oil to the steering cylinders as the steering wheel is rotated. Load sensing pressure is transmitted to the load sensing line through an orifice in the directional spool of the HMU. The load sensing pressure is proportional to the rotational speed of the steering wheel and the resistance to turn the machine. As the pressure in the load sense line increases, the directional control valve in the secondary steering pump will shift to the left and direct pump flow to tank. The secondary steering electric drive pump has a relief valve that limits the maximum pressure.
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Text Reference
137 HOIST HYDRAULIC SYSTEM The hydraulic system on the 735/740 trucks can be equipped with a dump body and hoist cylinders or an ejector system. The top left illustration shows a truck equipped with a dump body and the other illustrations show a truck equipped with an ejector body. The hydraulic system is electronically controlled by the Transmission/Chassis ECM. The main components of the electronic control system are the Transmission/Chassis ECM, the hoist control lever, and the pilot actuator solenoids on the hoist valve.
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Text Reference
1 4
138
5
139 3 2
The operator controls the hoist lever (1). There are four hoist lever positions on dump body trucks: RAISE, HOLD, FLOAT, and LOWER. There are three hoist lever positions on ejector body trucks: EJECT, HOLD, and RETRACT. The hoist lever controls a position sensor (2). The PWM sensor sends duty cycle input signals to the Transmission/Chassis ECM. The hoist lever position sensor is a Hall effect position sensor and operates the same as the transmission shift lever sensor (3) previously described.
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Text Reference
Depending on the position of the sensor and the corresponding duty cycle, one of the two solenoids located on the hoist valve is energized. The sensor provides a duty cycle signal that changes for all positions of the hoist lever so that the operator can modulate the speed of the hoist cylinders or ejector cylinder. The ECM will ignore requests from the operator if the hoist system is not functioning properly. The Transmission/Chassis ECM will force the hoist system into the HOLD position if any of the following problems occur: - The ECM detects faults in the hoist lever - The ECM detects faults in the hoist solenoids NOTE: The engine will not start until the hoist control lever is in the HOLD position. Also shown are the transmission shift lever (4) and the parking braking control button (5).
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Text Reference
1 140
2 141
The hoist pump is a gear pump that is located on the pump drive above the transmission on the left side of the machine. The top illustration shows the location of the hoist pump (1) on the 735 truck and the bottom illustration shows the location of the hoist pump (2) on the 740 truck. The hoist pump supplies oil to the hoist control valve.
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Text Reference
1
142
2 2
4
1
143
2
2 3
5
The hoist control valve (1) is located on the left side of the machine below the cab (as shown in the top illustration). The bottom illustration shows the opposite side of the hoist control valve. The hoist control valve directs oil from the hoist pump to the hoist cylinders or ejector control valve. The Transmission/Chassis ECM sends a signal to the hoist proportional solenoid valves (2) which control the pilot oil signal to the ends of the hoist control valve main spool. The pilot oil controls the position of the spool which controls hoist pump oil flow to the hoist cylinders or ejector control valve. The solenoid valves are energized when the hoist control lever is moved from the HOLD position. When the hoist control is in the HOLD position, the solenoid valves are de-energized.
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Text Reference
The main relief valve (3) limits oil pressure in the hoist circuit. The cooler relief valve (4) limits the oil pressure in the brake cooling circuit. The dead engine lowering valve (5) allows the dump body to be lowered if the engine will not run. The lowering valve connects the head end of the hoist cylinders to tank.
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To Brake Cooling
Text Reference
To Tank
Cooling Relief Valve
HOIST CONTROL VALVE HOLD
To Hoist Cylinder Head End
From Pump Raise Pilot Control Actuator
Lower Pilot Control Actuator
Main Relief Valve
Main Spool To Hoist Cylinder Rod End
Plug
Manual Lowering Valve
144
This illustration shows the hoist control valve in the HOLD position. In the HOLD position, the pilot control actuators are de-energized by the Transmission/Chassis ECM and the main spool is centered by the springs inside the pilot actuators. Oil from the pump is blocked by the main spool from flowing to the hoist cylinders or the ejector control valve. The main relief valve in the dump body trucks is a two stage relief valve (raise and lower). The main relief valve in the ejector trucks is a single stage relief valve. The dump body trucks are equipped with a manual lowering valve as shown in this illustration. The ejector trucks are equipped with an ejector cylinder head end relief valve rather that the manual lowering valve on the dump body trucks.
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Text Reference
HOIST CONTROL VALVE RAISE
To Brake Cooling
To Tank
Cooling Relief Valve
To Hoist Cylinder Head End
From Pump Raise Pilot Control Actuator
Lower Pilot Control Actuator
To Hoist Cylinder Rod End
Main Spool
145
When the hoist control lever is moved to the RAISE position, the Transmission/Chassis ECM sends a current to energize the raise pilot control actuator. Pilot oil is drained from the raise pilot control actuator and the main spool is moved fully to the left by the pilot pressure in the lower pilot actuator. Oil flows from the hoist pump port to the head end of the hoist cylinders. The hoist cylinders raise the dump body. Oil from the rod end of the hoist cylinders returns to the tank through the hoist control valve.
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Text Reference
146
1
2
147
A manifold (1) is used to divide the pump supply oil to each of the hoist cylinders on dump body trucks. The block is located on the front of the trailer. The manifold has a pressure tap (2) that is used to lower the body with a dead engine if the body is over center. The secondary steering pump is used to send oil to the rod end of the hoist cylinders through the manifold pressure tap to lower the body. NOTE: Refer to the procedure in the Operation and Maintenance Manual to manually lower the body with the engine stopped.
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Text Reference
3
1
148
1
149
2
The hoist cylinders (1) are located on the frame rails of the trailer. The hoist cylinders are double acting cylinders. The dump body prop (2) must be installed on the hoist cylinders when servicing the truck with the dump body raised. NOTE: Most machines are equipped with a manual tailgate release, which uses a chain (3) to release the tailgate.
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Text Reference
4 1 3
2
150
The hydraulic tank (1) is located on the left side of the machine near the cab. The hydraulic tank holds oil for the hoist and brake systems. The hydraulic tank contains a return filter that is accessed by removing a cover (2). Also located on the top of the tank is the tank breather (3) and the fill cap (4). The oil level sight gauge (not visible) is located on the left side of the machine in front of the left tire. A tank breather is also located on the top of the tank.
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Text Reference
HOIST CONTROL SYSTEM HOLD
Brake Oil Pressure Switch
To Service Brake Valve To Service Brake Valve Check and Pressure Reducing Valve Manifold
To Parking Brake Valve Brake System Relief Valve
Pilot Reducing Valve
Transmission Pump Drive Hoist Pump
Engine
Main Relief Valve
Brake Pump
Hoist and Brake Hydraulic Tank
Lower Pilot Actuator
Cooling Relief Valve
Manual Lowering Valve
Hoist Control Valve
Hoist Cylinder
Tailgate Cylinder
Raise Pilot Actuator
To Brake Cooling
Relief Valve Hoist Cylinder
151
Hoist Hydraulic System - Dump Body In the HOLD position, the pilot control actuator solenoids are de-energized and the hoist control valve spool is centered. Oil is blocked from flowing to the hoist cylinders. Oil to the pilot actuators is provided by the brake pump. A pressure reducing valve in the check and pressure reducing valve manifold reduces the brake oil pressure to pilot pressure. The hoist pump provides the oil to move the cylinders. In the HOLD position, oil from the hoist pump is allowed to flow through the center port of the hoist main spool to the brake cooling system. Return brake cooling oil is monitored by a temperature switch which reports any overheat condition in the brake system. These switches will initiate an illuminated brake temperature warning if either switch opens indicating an overheating condition. An event code will be logged if either switch has been in the fault state for over 5 seconds and the engine is running. With a non running engine, a Level 2 Warning is initiated. A running engine, initiates a Level 2S Warning. In the event of a dead engine, the manual lowering valve is used to drain oil from the head end of the hoist cylinders to lower the dump body.
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Text Reference
HOIST CONTROL SYSTEM RAISE
Brake Oil Pressure Switch
To Service Brake Valve To Service Brake Valve Check and Pressure Reducing Valve Manifold
To Parking Brake Valve Brake System Relief Valve
Pilot Reducing Valve
Transmission Pump Drive Hoist Pump
Engine
Main Relief Valve
Brake Pump
Hoist and Brake Hydraulic Tank
Lower Pilot Actuator
Cooling Relief Valve
Manual Lowering Valve
Hoist Control Valve
Hoist Cylinder
Tailgate Cylinder
Raise Pilot Actuator
To Brake Cooling
Relief Valve Hoist Cylinder
152
When the hoist control lever is moved to the RAISE position, a pulse width modulated signal is sent to the Transmission/Chassis ECM. The ECM sends a proportional amount of current to the raise pilot control actuator. When the raise pilot control actuator is energized, the actuator will drain pilot oil from between the actuator and the end of the control spool. The hoist control valve moves down and the upper envelope is highlighted. The hoist control valve directs hoist pump supply oil to the head end of the hoist cylinders. The hoist cylinder return oil flows from the rod end of the hoist cylinders into the hoist control valve and is directed to the port for brake cooling. If the truck is equipped with a tail gate cylinder to open the gate, the supply oil will also flow into the rod end of the cylinder when the the hoist control lever is moved to the RAISE position. As the cylinder begins to retract, the oil pressure at the head end flows to the check valve and is blocked. Oil pressure increases, which opens the relief valve and allows the cylinder to retract fully and open the tailgate.
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Text Reference
HOIST CONTROL SYSTEM LOWER
Brake Oil Pressure Switch
To Service Brake Valve To Service Brake Valve Check and Pressure Reducing Valve Manifold
To Parking Brake Valve Brake System Relief Valve
Pilot Reducing Valve
Transmission Pump Drive Hoist Pump
Engine
Main Relief Valve
Brake Pump
Hoist and Brake Hydraulic Tank
Lower Pilot Actuator
Cooling Relief Valve
Manual Lowering Valve
Hoist Control Valve
Hoist Cylinder
Tailgate Cylinder
Raise Pilot Actuator
To Brake Cooling
Relief Valve Hoist Cylinder
153
As the operator moves the hoist control lever into the LOWER position, a pulse width modulated signal is sent to the Transmission/Chassis ECM. The ECM sends a proportional amount of current to the lower pilot control actuator. When the lower pilot control actuator is energized, the actuator will drain pilot oil from between the actuator and the end of the control spool. The hoist control valve moves up and the lowest envelope is highlighted. The hoist control valve directs hoist pump supply oil to the rod end of the hoist cylinders. The hoist cylinder return oil flows from the head end of the hoist cylinders to the tank. If the truck is equipped with a tail gate cylinder to open the gate, the supply oil will flow into the head end of the cylinder. As the cylinder begins to extend, the oil in the rod end flows to through the hoist control valve and back to the hydraulic tank. The tail gate will close.
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Text Reference
HOIST CONTROL SYSTEM FLOAT
Brake Oil Pressure Switch
To Service Brake Valve To Service Brake Valve Check and Pressure Reducing Valve Manifold
To Parking Brake Valve Brake System Relief Valve
Pilot Reducing Valve
Transmission Pump Drive Hoist Pump
Engine
Main Relief Valve
Brake Pump
Hoist and Brake Hydraulic Tank
Lower Pilot Actuator
Cooling Relief Valve Raise Pilot Actuator
To Brake Cooling
Manual Lowering Valve
Hoist Control Valve
Hoist Cylinder
Tailgate Cylinder
Relief Valve Hoist Cylinder
154
As the operator moves the hoist control lever into the FLOAT position, a pulse width modulated signal is sent to the Transmission/Chassis ECM. The ECM sends a proportional amount of current to the lower pilot control actuator. When the lower pilot control actuator is energized, the actuator will drain pilot oil from between the actuator and the end of the control spool. The hoist control valve moves up and the float envelope is highlighted. The hoist control valve directs a metered amount of hoist pump supply oil to the rod end of the hoist cylinders and also directs oil to the brake cooling system The hoist cylinder return oil flows from the head end of the hoist cylinders to the tank. If the truck is equipped with a tail gate cylinder to open the gate, the supply oil will flow into the head end of the cylinder. As the cylinder begins to extend, the oil in the rod end flows to through the hoist control valve and back to the hydraulic tank. The tail gate will close.
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Text Reference
155
2
3 3
1
156
1
Hoist Hydraulic System - Ejector Body The ejector cylinder (1) is a three-stage telescoping cylinder. The ejector blade (2) is located in the bed. The ejector blade is moved forward and backward by the ejector cylinder. The ejector travels on rollers (3) on the bottom and sides of the ejector assembly.
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Text Reference
2
3 1
157
The tailgate (1) is located at the back of the bed. The tailgate is hydraulically raised and lowered by the tailgate cylinders (not visible) located behind a panel (2) on each side of the truck. The head end of the cylinder is connected to the truck bed and the rod end of the cylinder is connected to the linkage (3) which opens the tailgate. When the tailgate cylinders retract, the tailgate opens. When the tailgate cylinders extend, the tailgate closes.
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Text Reference
13
14
12
2 15
1
3
11 4
5
6
7
8 10 9
158 The ejector manifold (1) is located on the front of the rear frame as shown in the top left illustration. The ejector manifold controls the operation of the ejector cylinder and the tailgate cylinders. The following components are located on the right side of the ejector control valve: - Flow regulator (2) - Check valve (3) The following components are located on the front of the ejector control valve: - Load control valve (4) - Flow regulator (5) - Load control valve (6) - Sequence valve (7) - Relief valve (8) - Diverter valve (9)
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Text Reference
The following components are located on the left side of the ejector control valve: - Sequence valve (10) - Pressure tap for head end of ejector cylinder (11) The following components are located on the top of the ejector control valve: - Pressure tap for rod end of ejector cylinder (12) - Orifice (13) - Diverter valve (15) - Check valve (14)
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Text Reference
EJECTOR MANIFOLD HOLD
Ejector Cylinder
From Ejector Valve
Sequence Valve (10)
From Retract Pilot Actuator From Brake Pump
8:1 Load Control (6)
Diverter Valve (9) Sequence Valve (7)
Check Valve (3) Orifice (13)
Check Valve (14)
Line Relief Valve (8)
Diverter Valve (15) From Eject Pilot Actuator
Flow Regulator (2) Flow Regulator (5)
3:1 Load Control (4)
Ejector Manifold (1)
Tailgate Cylinders
159
The ejector manifold directs oil from the hoist pump via the ejector control valve to the head end of the ejector cylinder and to the rod end of the tailgate cylinders. The ejector manifold also directs oil from the brake pump to the head end and rod end of the ejector cylinder and to the head end and rod end of the tailgate cylinders. Oil flow from the hoist pump is used to extend the ejector cylinder (EJECT position) and retract the tailgate cylinders (OPEN position). Oil from the brake pump is used to retract the ejector cylinder (RETRACT position) and extend the tailgate cylinders (CLOSE position). Oil from the brake pump also combines with oil from the hoist pump to extend the ejector cylinder and retract the tailgate cylinders. Oil from the brake pump is constantly supplied to the sequence valve (7) through the check valve (14). The sequence valve (7) blocks the brake pump oil when the ejector control valve is in the HOLD position as shown in this illustration. NOTE: The sequence valve (7) ensures that the braking system is charged before oil is allowed to flow from the braking system into the ejector system.
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Text Reference
When the ejector is activated, the lower diverter valve (15) moves and allows oil from the top of the sequence valve to drain to tank. The diverter valve is moved by oil pressure from the eject or retract pilot actuator. Oil from the brake pump is now allowed to flow from the sequence valve to the following locations: - Upper diverter valve (9) - Rod end of the ejector cylinder - Line relief valve (8) - Through the check valve (3) and orifice to the head end of the tailgate cylinders - Through the check valve (3) and orifice to the lower load control valve (4) - Through the check valve (3), the orifice, and the upper flow regulator (2), to the upper load control valve (6) when the flow regulator (2) is open three turns. In the EJECT position, the upper diverter valve (9) will allow oil from the brake pump to flow to the upper sequence valve (10). The sequence valve (10) opens and brake oil combines with the hoist pump oil and flows to the head end of the ejector cylinder and to the rod end of the tailgate cylinders. The upper flow regulator (2) and the load control valves are used to control the return oil from the rod end of the ejector when the ejector system is in the EJECT position. The load control valves are opened by oil pressure in the head end of the ejector cylinder. The upper flow regulator (2) determines the load control valve that is used to return oil from the rod end of the ejector to the tank. The upper flow regulator (2) is manually adjusted for light or heavy material. For light material, the upper flow regulator (2) opens and the 8:1 load control valve (6) opens to allow oil from the rod end of the ejector cylinder and head end of the tailgate cylinders to return to the tank. For normal to heavy material, the upper flow regulator (2) is closed and the 3:1 load control valve (4) is opened to allow oil from the rod end of the ejector cylinder and head end of the tailgate cylinders to return to the tank. The lower flow regulator (5) is used to manually lower the tailgate and is closed during normal operation. The primary function of the upper sequence valve (10) is to control the ejector cylinder from mistaging. When no load is applied against the ejector, multistage cylinders can start extending out of order which blocks the internal timing galleries as the cylinder reaches the end of its stroke. High pressure can result, which can damage the cylinder tubes. To prevent cylinder mistaging, the upper sequence valve (10) increases the ejector cylinder rod end oil pressure before opening so that as the cylinder extends, the increased back pressure will ensure the cylinder stages correctly. Therefore, the sequence valve must be set properly.
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Text Reference
Brake / Pilot Manifold To Service Brake Valve
To Service Brake Valve
Brake Oil Pressure Switch To Parking Brake Valve Brake System Relief Valve
Pilot Reducing Valve
Transmission Pump Drive
EJECTOR HYDRAULIC SYSTEM HOLD
Hoist Pump
Engine
To Brake Cooling
Main Relief Valve
Line Relief Valve
Retract Pilot Control Actuator
Ejector Cylinder
Sequence Valve Diverter Valve
Brake Pump
Cooling Relief Valve
Extend Pilot Control Actuator
Ejector Control Valve
Sequence Valve
8:1 Load Control Flow Regulator Check Valve Orifice
Check Valve Diverter Valve
Line Relief Valve
3:1 Load Control Flow Regulator
Ejector Manifold Tailgate Cylinders
160
In the HOLD position, the pilot control actuator solenoids are de-energized and the ejector control valve spool is centered. Hoist pump oil is blocked from flowing to the ejector manifold but is allowed to flow through the center port of the ejector main spool to the brake cooling system. Pilot oil flows from the pressure reducing valve to the pilot control actuators and to each end of the diverter valve and the shuttle valve. The upper diverter valve is moved left and the lower diverter valve is centered, which keeps the lower sequence valve from opening. With the lower diverter valve closed, oil from the brake pump is blocked at the lower sequence valve. Oil will not flow to the ejector cylinder or the tailgate cylinders. The ejector control valve on the ejector trucks contains two relief valves. The main relief valve limits the hoist circuit pressure and the line relief valve limits ejector cylinder head end pressure and tailgate cylinder rod end pressure.
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Text Reference
Brake / Pilot Manifold To Service Brake Valve
Brake Oil Pressure Switch To Parking Brake Valve
To Service Brake Valve Brake System Relief Valve
Pilot Reducing Valve
Transmission Pump Drive
EJECTOR HYDRAULIC SYSTEM BLADE EXTEND - HEAVY MATERIAL
Hoist Pump
Engine
To Brake Cooling
Main Relief Valve
Line Relief Valve
Retract Pilot Control Actuator
Ejector Cylinder
Sequence Valve Diverter Valve
Brake Pump
Cooling Relief Valve
Extend Pilot Control Actuator
Ejector Control Valve
Sequence Valve
Flow Regulator Check Valve Orifice
Check Valve Diverter Valve
8:1 Load Control
Line Relief Valve
3:1 Load Control Flow Regulator
Ejector Manifold Tailgate Cylinders
161
When the hoist control lever is moved to the EJECT position, a pulse width modulated signal is sent to the Transmission/Chassis ECM. The ECM sends a proportional amount of current to the eject pilot control actuator. When the eject pilot control actuator is energized, the actuator will drain pilot oil from between the actuator and the end of the control spool. The ejector control valve moves down and the upper envelope is highlighted. The ejector control valve directs hoist pump supply oil to the head end of the ejector cylinder and to the rod end of the tailgate cylinders. The retract pilot control actuator directs pilot oil to the left end of both diverter valves. The pilot pressure moves both diverter valves to the right. The lower sequence valve opens when oil is drained from the top of the lower sequence valve through the lower diverter valve. With the lower sequence valve open and the upper diverter valve moved to the left, oil from the brake pump flows through the lower sequence valve, the upper diverter valve, and the upper sequence valve to the head end of the ejector cylinder. Brake pump oil is combined with hoist pump oil to extend the ejector cylinder.
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Text Reference
Oil from the rod side of the ejector cylinder flows into the ejector manifold and also combines with oil that is flowing from the brake pump to the head end of the ejector cylinder. The combined oil the ejector cylinder to extend more rapidly. Oil also flows from the ejector manifold to the rod end of the tailgate cylinders. Oil is forced from the head end of the tailgate cylinders and back into the ejector manifold. Return oil from the head end of the tailgate cylinders flows to the tank through one of the load control valves. The load control valves are opened by oil pressure in the head end of the ejector cylinder and the rod end of the tailgate cylinders. The upper flow regulator determines the load control valve that is used. In this illustration, the upper flow regulator is closed because the blade is extending with a heavy load. Return oil from the head end of the tailgate cylinders returns to the tank through the 3:1 load control valve. The 3:1 load control valve opens at a higher pressure than the 8:1 load control valve. If the blade is extending with a light load, the upper flow regulator is open. Return oil from the head end of the tailgate cylinders returns to the tank through the 8:1 load control valve. The 8:1 load control valve opens at a lower pressure than the 3:1 load control valve. The lower flow regulator is used for manually lowering the tailgate. The lower flow regulator is closed during normal operation. The line relief valve in the ejector control valve limits the oil pressure in the head end of the ejector cylinder.
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Text Reference
Brake / Pilot Manifold To Service Brake Valve
Brake Oil Pressure Switch To Parking Brake Valve
To Service Brake Valve Brake System Relief Valve
Pilot Reducing Valve
Transmission Pump Drive
EJECTOR HYDRAULIC SYSTEM BLADE RETRACT
Hoist Pump
Engine
To Brake Cooling
Main Relief Valve
Line Relief Valve
Retract Pilot Control Actuator
Ejector Cylinder
Sequence Valve Diverter Valve
Brake Pump
Cooling Relief Valve
Extend Pilot Control Actuator
Ejector Control Valve
Sequence Valve
8:1 Load Control Flow Regulator Check Valve Orifice
Check Valve Diverter Valve
Line Relief Valve
3:1 Load Control Flow Regulator
Ejector Manifold Tailgate Cylinders
162 When the hoist control lever is moved to the RETRACT position, a pulse width modulated signal is sent to the Transmission/Chassis ECM. The ECM sends a proportional amount of current to the retract pilot control actuator. When the retract pilot control actuator is energized, the actuator will drain pilot oil from between the actuator and the end of the control spool. The hoist control valve moves up and the lower envelope is highlighted. The hoist control valve directs hoist pump supply oil to the brake cooling system. The eject pilot control actuator directs pilot oil to the right end of both diverter valves. The pilot pressure moves the diverter valves to the left. The lower sequence valve opens when oil is drained from the top of the lower sequence valve through the lower diverter valve. With the lower sequence valve open and the upper diverter valve moved to the left, oil from the brake pump flows through the lower sequence valve to the rod end of the ejector cylinder. Oil also flows through a check valve and orifice to the head end of the tailgate cylinders. The ejector cylinder retracts and the tailgate closes. Oil returns from the head end of the ejector cylinder and the rod end of the tailgate cylinders to the tank through the ejector control valve. The line relief valve in the ejector manifold limits the oil pressure in the rod end of the ejector cylinder.
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Text Reference
163 1
2 3
164
1
BRAKE SYSTEM The brake pump (1) is located on the left side of the engine and is driven by the engine drive train gears. The brake pump is a variable displacement pump that provides oil to the brake hydraulic system and the hoist pilot hydraulic system. The pump control valve contains a margin valve (2) and a pressure cutoff valve (3). The pressure cutoff valve controls the pressure in the brake hydraulic circuit. NOTE: The margin valve spool is bottomed out and is not used in the 735/740 brake hydraulic system.
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Text Reference
2 3
1 4
165
The brake check and pressure reducing valve is located below the cab. The check and pressure reducing valve contains two check valves (1), a relief valve (2), and a pressure reducing valve (3). The check and pressure reducing valve divides the oil flow between the service brake accumulators and the hoist pilot control actuators. The check valves ensure the accumulators remain charged when pressure decreases between the pump and accumulators. The pressure reducing valve reduces the brake oil system pressure to pilot pressure that is used for the hoist pilot control actuators. The relief valve limits brake hydraulic system pressure if the pump pressure cutoff valve is not operating correctly. The service brake pressure switch (4) is also located on the check and pressure reducing valve. The pressure switch sends a signal to the Transmission/Chassis ECM indicating service brake pressure.
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Text Reference
166
The service brake accumulators (arrows) are located on the right side of the operator's station. The accumulators are used to engage the service brakes if the engine is not operating. The accumulators are a rubber diaphragm type that contain oil and nitrogen. The accumulators can be charged, but not repaired. A faulty accumulator must be replaced. NOTE: In colder temperatures (arctic package) a piston is used rather than a diaphragm in the brake accumulators.
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Text Reference
167
1
3
168 2
The brake control valve (1) is located at the front of the operator’s station. The brake control valve controls the application of the service brakes by directing oil from the brake accumulators to the service brakes. The brake control valve controls the release of the brakes by directing oil from the service brakes back to the hydraulic tank. Two pressure switches for the brake system are located in a manifold at the front of the operator’s station. The two pressure switches are the transmission signal pressure switch (2) and the stop light pressure switch (3). Both switches will be discussed later in the brake system presentation.
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Spring
Text Reference
SERVICE BRAKE CONTROL VALVE
Check Valve To Front Brakes
To Tank Front Axle Spool
From Front Brake Accumulator
Rear Axle Spool
To Tank
To Rear Brakes From Rear Brake Accumulator
169
This illustration shows the internal components of the brake control valve. The service brake control valve is a dual pressure reducing valve with two independent output pressures. The service brake control valve modulates pressurized oil from the brake accumulators to the service brake section of the wheel brakes. The position of the service brake pedal controls the pressure at the brakes. If one braking circuit fails, the second braking circuit remains functional due to the mechanical contact between the upper and lower valve spools. With the engine running, oil flows from the accumulators into the service brake control valve. When the operator pushes on the service brake pedal, springs cause the upper and lower spools to overcome the spring force and move down. When the upper spool moves down, oil from the accumulator port flows to the rear brakes. The upper spool also causes the lower spool to move down. As the lower spool moves down, oil flows to the front brakes.
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3
Text Reference
1
2
4
170
This illustration shows the right rear axle and final drive housing. The service brake is installed between the axle and the final drive housing. When the pedal in the cab is pressed, brake oil flows through the brake supply port (1) into the brake chamber to engage the service brakes. The service brakes are cooled by oil from the hoist system. Cooling oil flows through the cooling port (2) into the brake cooling chamber to cool the brakes. The cooling oil flows from the cooling port (3) to the hoist and brake hydraulic tank. Test equipment can be installed after removing a plug on the brake housing to check and adjust the service brakes. There are three plugs on each brake group. Two plugs (4) are visible in this illustration.
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Text Reference
1
3
2
171 The service brakes on the 735/740 trucks are oil cooled. The brake oil cooler (1) is located on the right side of the engine. Oil flows through the service brakes and heat is transferred from the service brakes to the oil. The oil then flows to the tank. The front temperature sensor (2) and rear temperature sensor (3) send a signal to the Transmission/Chassis ECM indicating brake oil temperature. The front temperature sensor is located below the cab on the left side of the machine. The rear temperature sensor is located in a manifold on the rear frame.
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Text Reference
1 2
3
4
172
The parking brake control valve (1) is located on the inside of the left frame rail. When the parking brake switch in the cab is activated, a signal is sent to the Transmission/Chassis ECM. The ECM sends a corresponding signal to the parking brake solenoid (2), which directs oil to engage or release the parking brake. The parking brake accumulator (3) provides oil to disengage the parking brake if the engine is not operating. The accumulator is a rubber diaphragm-type. The accumulators can not be repaired. A faulty accumulator must be replaced. The parking brake pressure switch (4) is also located on the parking brake control valve. The pressure switch sends a signal to the Transmission/Chassis ECM indicating parking brake oil pressure.
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Text Reference
3
173 3 1
2
174
4
The parking brake is located on the center axle. The parking brake is a spring applied, hydraulically released brake. Oil enters the actuator (1) and compresses the spring inside. The actuator rod (2) moves outward and releases the brake discs (3) from the parking brake rotor (4). Oil is drained from the actuator when the parking brake solenoid is de-energized. The spring inside the actuator pulls the actuator rod inward and the brake shoes clamp down on the parking brake rotor.
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Text Reference
BRAKE HYDRAULIC SYSTEM
SERVICE BRAKES RELEASED / PARKING BRAKE ENGAGED Service Brake Control Valve
Parking Brake Accumulator
Service Brake Accumulators
Parking Brake Pressure Switch
Brake Oil Pressure Switch
Check and Pressure Reducing Valve
Parking Brake Control Valve
Relief Valve Front Service Brake
Parking Brake Actuator
Pilot Reducing Valve
To Hoist Pilot Valves
Rear Service Brakes
Engine
Front Service Brake
From Hoist Valve
Brake Pump
Front Brake Temp Sensor
Rear Brake Temp Sensor
Hoist and Brake Hydraulic Tank
175
This illustration shows the brake hydraulic system with the service brakes RELEASED and the parking brake ENGAGED. Oil flows from the brake pump and enters the check and pressure reducing valve and begins to charge the brake accumulators. Oil also flows to the parking brake control valve and the service brake control valve. With the brake pedal released, oil is blocked at the service brake control valve and oil from the service brakes flows to the tank. The service brakes are released. When the parking brake switch is activated, the Transmission/Chassis ECM sends a signal to de-energize the parking brake solenoid. Oil is blocked at the parking brake solenoid and spring force inside the parking brake actuator moves the actuator rod to engage the parking brake.
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Text Reference
BRAKE HYDRAULIC SYSTEM
SERVICE BRAKES ENGAGED / PARKING BRAKE RELEASED Service Brake Control Valve
Parking Brake Accumulator
Service Brake Accumulators
Parking Brake Pressure Switch
Brake Oil Pressure Switch
Check and Pressure Reducing Valve
Parking Brake Control Valve
Relief Valve Front Service Brake
Parking Brake Actuator
Pilot Reducing Valve
To Hoist Pilot Valves
Rear Service Brakes
Engine
Front Service Brake
From Hoist Valve
Brake Pump
Front Brake Temp Sensor
Rear Brake Temp Sensor
Hoist and Brake Hydraulic Tank
176
This illustration shows the brake hydraulic system with the service brakes ENGAGED and the parking brake RELEASED. Oil flows from the brake pump and enters the check and pressure reducing valve and begins to charge the brake accumulators. Oil also flows to the parking brake control valve and the service brake control valve. There are two spools inside the service brake control valve which are offset when the pedal is pressed. The top spool controls the oil supply to the front service brakes and the lower spool controls the oil supply to the rear service brakes. The oil pressure in the brake lines is transmitted to the underside of the top spool and the lower spool through internal passages when the brakes engage. As the pressure increases the top spool and the lower spool move up to the center position. The center position maintains a constant pressure in the brakes. With the brake pedal depressed, the service brake control valve directs oil to the service brakes and the service brakes engage to slow or stop the machine.
SERV1838 06/07
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Text Reference
When the parking brake switch is de-activated, the Transmission/Chassis ECM sends a signal to energize the parking brake solenoid. The parking brake solenoid directs oil to the parking brake actuator. The oil pressure works against the spring force inside the parking brake actuator, which moves the actuator rod to release the parking brake. The parking brake pressure switch closes and the Transmission/Chassis ECM turns off the parking brake indicator in the cab when the parking brake is released.
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Text Reference
177
1
2 3 178 4
SUSPENSION SYSTEM The front suspension cylinders (1) are attached to the front axle and the frame. The suspension cylinders are filled with oil and nitrogen. The front suspension cylinders provide shock absorption between the front wheels and the frame. Each front suspension cylinder has three ports. The Port O (2) is used to fill the cylinder with oil. The Port N (3) is used to fill the cylinder with nitrogen. The Port (4) is used as a drain port when draining or filling the suspension cylinder.
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Text Reference
1
2
3
179
The rear suspension arm (1) allows the rear axles to follow the contours of the terrain. The suspension blocks (2) help to cushion the frame from sudden movements of the axles. A suspension link (3) is located at the back of each rear axle. One end of the link is attached to the axle and the other end is attached to the frame. Suspension links give the rear axles a large amount of articulation.
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Text Reference
180
1
2
3 181
Adjusting The Suspension Height Fully lower the front suspension by draining the oil and nitrogen into a suitable container. Measure the height on both sides of the machine from the top of the rim to the bottom of the fender (Dimension A). Record the measurement from each side. Open all three ports. Inject oil in the port (1) until oil flows out of the port (3). Close the port (3) Continue to inject oil until oil flows out of the port (2). Close the port (2). Leave the port (1) open. Begin to charge the suspension cylinder with nitrogen in the port (2). Oil will flow out of the port (1). Continue to fill the port (2) until only nitrogen comes out of the port (1), then close the port (1).
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Text Reference
Continue to fill the port (2) with nitrogen till the suspension cylinder raises 10 mm (0.4 in). Repeat the procedure for the other cylinder. Raise the suspension evenly in 10 mm (0.4 in) increments. The final suspension height should be the Dimension A measurement (which is measured at the start of the procedure) plus 75 ± 10 mm (3 ± 0.4 in).
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Text Reference
182
CONCLUSION This presentation has provided a basic introduction to the Caterpillar 735/740 Articulated Dump Trucks. All the major component locations were identified and the major systems were discussed. When used in conjunction with the service manual, the information in this package should permit the technician to analyze problems in any of the major systems on these trucks.
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Text Reference
VISUAL LIST 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43.
Model view Operator's station Dash Cluster display Retarder control Hoist control lever Relay panel Machine electronic control system block diagram Messenger display Messenger display navigation buttons Messenger menu screen Messenger information screen Messenger main menu Performance menu Performance menu options Operator menu Operator menu options Totals menu Totals menu options Settings menu Settings menu options Service menu Service menu options C15 ACERT™ engine Engine features Engine electrical block diagram Engine ECM Calibration connector Primary engine speed/timing sensor Secondary engine speed/timing sensor Coolant temperature sensor Start relay High coolant temperature derate Intake manifold air temperature sensor Intake manifold air temperature sensor derate Atmospheric pressure sensor Low oil pressure derate Virtual exhaust temperature derate Turbocharger inlet pressure sensor Air inlet restriction derate Fuel delivery system block diagram Power derate Fuel transfer pump
44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57. 58. 59. 60. 61. 62. 63. 64. 65. 66. 67. 68. 69. 70. 71. 72. 73. 74. 75. 76. 77. 78. 79. 80.
Primary fuel filter Secondary fuel filter Differential fuel pressure switch Fuel temperature derate High fuel filter restriction derate Pedals Throttle position sensor Engine compression brake Engine compression brake basics Engine brake - DISABLED Engine brake - ENABLED AND BEFORE TDC Engine brake - ENABLED AND PISTON AT TDC Engine brake - ENABLED AND PISTON AFTER TDC Fan pump on 735 trucks Fan and steering pumps on 740 trucks Fan motor Fan solenoid and remote pressure tap fitting Radiator Cooling fan hydraulic system schematic Air to air aftercooler hydraulic schematic ATAAC hydraulic gear pump and fuel transfer pump Hydraulic motor Power train Power train system components Transmission/Chassis ECM Transmission shift lever circuits Transmission electronic control system components 735 transmission electronic control system diagram 735 truck ECPC transmission components Engine speed sensor on 735 trucks Torque converter oil temperature sensor on 735 trucks 735 transmission hydraulic system components Torque converter Torque converter - CONVERTER DRIVE Torque converter - DIRECT DRIVE 735 transmission planetary Transmission clutch engagement chart
SERV1838 06/07
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Text Reference
VISUAL LIST 81. 735 transmission hydraulic system NEUTRAL 82. Transmission oil cooler 83. Transmission modulating valve - NO COMMANDED SIGNAL 84. Transmission modulating valve COMMANDED SIGNAL BELOW MAXIMUM 85. Transmission modulating valve COMMANDED SIGNAL AT MAXIMUM 86. Main relief valve 87. 740 transmission electronic control system diagram 88. 740 transmission components 89. Transmission gear position switch 90. Engine speed sensor on 740 trucks 91. Torque converter oil temperature sensor on 740 trucks 92. 740 transmission hydraulic system components 93. Lockup clutch modulating valve 94. 740 torque converter 95. Torque converter - CONVERTER DRIVE 96. Torque converter - DIRECT DRIVE 97. 740 transmission planetary 98. Transmission clutch engagement chart 99. 740 transmission arrangement 100. Transmission hydraulic system NEUTRAL 101. Transmission hydraulic system DOWNSHIFTING TO NEUTRAL 102. Selector valve group - NEUTRAL 103. Pressure control valve - NEUTRAL 104. Valve station - CLUTCH RELEASED 105. Valve station - CLUTCH FILLING 106. Valve station - CLUTCH ENGAGED 107. Valve station - CLUTCH DECAY 108. Shift cycle 109. Clutch fill and modulation problems 110. Differential system 111. Interaxle differential 112. Differential input shaft 113. Planet carriers 114. Planet gears
115. 116. 117. 118. 119. 120. 121. 122. 123. 124. 125. 126. 127. 128. 129. 130. 131. 132. 133. 134. 135. 136. 137. 138. 139. 140. 141. 142. 143. 144. 145. 146. 147. 148. 149. 150. 151. 152. 153. 154.
Sun gear Differential gears Differential plates Solenoid relief valve Orifice Output transfer gear oil filter OTG temperature sensor Differential lock system - INTER-AXLE OFF Differential lock system - INTER-AXLE ON Differential lock system - INTER-AXLE AND CROSS-AXLE ON Steering system components 735 steering pump 740 steering pump Hydraulic tank Steering check and combiner valve Hand metering unit Steering cylinder Steering system schematic - HOLD Steering system schematic - RIGHT TURN Secondary steering system pump Secondary steering system schematic HOLD Secondary steering system schematic RIGHT TURN Hoist hydraulic system Hoist lever Transmission shift lever sensor 735 hoist pump 740 hoist pump Hoist control valve Main relief valve Hoist control valve - HOLD Hoist control valve - RAISE Manifold Manifold pressure tap Hoist cylinders Dump body prop Hydraulic tank Hoist control system schematic - HOLD Hoist control system schematic - RAISE Hoist control system schematic - LOWER Hoist control system schematic - FLOAT
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VISUAL LIST 155. 156. 157. 158. 159. 160. 161. 162. 163. 164. 165. 166. 167. 168. 169. 170. 171. 172. 173. 174. 175.
176.
177. 178. 179. 180. 181. 182.
Ejector blade Ejector cylinder Tailgate Ejector manifold Ejector manifold - HOLD Ejector hydraulic system schematic - HOLD Ejector hydraulic system schematic BLADE EXTEND Ejector hydraulic system schematic BLADE RETRACT Brake pump Margin valve and pressure cutoff valve Brake check and pressure reducing valve Service brake accumulators Brake control valve Transmission signal pressure switch and stop light pressure switch Service brake control valve Right rear axle and final drive housing Brake cooling components Parking brake control valve Parking brake actuator Parking brake rotor Brake hydraulic system schematic SERVICE BRAKE RELEASED/PARKING BRAKE ENGAGED Brake hydraulic system schematic SERVICE BRAKE ENGAGED/PARKING BRAKE RELEASED Front suspension cylinders Front suspension cylinder ports Rear suspension Adjusting suspension height Front suspension oil ports Model view
Text Reference
SERV1838 06/07
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Text Reference
HYDRAULIC SCHEMATIC COLOR CODE Black - Mechanical Connection. Seal
Red - High Pressure Oil
Dark Gray - Cutaway Section
Red / White Stripes - 1st Pressure Reduction
Light Gray - Surface Color
Red Crosshatch - 2nd Reduction in Pressure
White - Atmosphere or Air (No Pressure)
Pink - 3rd Reduction in Pressure
Purple - Pneumatic Pressure
Red / Pink Stripes - Secondary Source Oil Pressure
Yellow - Moving or Activated Components
Orange - Pilot, Charge or Torque Converter Oil
Cat Yellow - (Restricted Usage) Identification of Components within a Moving Group
Orange / White Stripes - Reduced Pilot, Charge, or TC Oil Pressure
Brown - Lubricating Oil
Orange / Crosshatch - 2nd Reduction in Pilot, Charge, or TC Oil Pressure
Green - Tank, Sump, o r Return Oil
Blue - Trapped Oil
Green / White Stripes Scavenge / Suction Oil or Hydraulic Void
HYDRAULIC SCHEMATIC COLOR CODE This illustration identifies the meanings of the colors used in the hydraulic schematics and cross-sectional views shown throughout this presentation.
Blue - Trapped Oil
Green - Tank, Sump, o r Return Oil
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Green / White Stripes Scavenge / Suction Oil or Hydraulic Void
Orange / Crosshatch - 2nd Reduction in Pilot, Charge, or TC Oil Pressure
Orange / White Stripes - Reduced Pilot, Charge, or TC Oil Pressure
Cat Yellow - (Restricted Usage) Identification of Components within a Moving Group
Brown - Lubricating Oil
Orange - Pilot, Charge or Torque Converter Oil
Red / Pink Stripes - Secondary Source Oil Pressure
Pink - 3rd Reduction in Pressure
Yellow - Moving or Activated Components
Purple - Pneumatic Pressure
White - Atmosphere or Air (No Pressure)
Red Crosshatch - 2nd Reduction in Pressure
Red / White Stripes - 1st Pressure Reduction
Dark Gray - Cutaway Section
Light Gray - Surface Color
Red - High Pressure Oil
Black - Mechanical Connection. Seal
HYDRAULIC SCHEMATIC COLOR CODE
SERV1838 06/07 Handout No. 1
This will be raised after the switch has been in the fault state for 5 sec and the engine is running. If the engine is not running, the level is 2. If the engine is running, the level is 2S.
High Front Brake Oil Temperature
Hydraulic Oil Filter Steer Tank Bypass Switch is open indicating that the filter is blocked. Air Filter is restricted with a 7.5 kPa (1.1 psi) pressure difference. Air Filter is restricted with a 9 kPa (1.3 psi) pressure difference.
Hydraulic Oil Filter Steer Tank Blocked
Engine Air Filter Restricted
Engine Air Filter Restricted
Output Transfer Gear Filter Blocked
OTG Filter Bypass Switch is open indicating that the filter is blocked and the oil temp is greater than 38 C (100.4 F). Disabled if the oil temp is less than 27 C (80.6 F).
Transmission Filter Bypass Switch is open indicating that the filter is blocked and the oil temp. is greater than 51 C (123.8 F). Disabled if the oil temp. is less than 43 C (109.4 F)
Transmission Filter is Restricted (NOT On 740)
High Rear Brake Oil Temperature
Warning Condition
Warning Condition
2
272
272
281
328
107 Rear
106 Front
329
EID on Right Display
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1
3
3
2/2s
3
Warning Level
Monitoring System Warning Conditions
SERV1838 06/07 Handout No. 2
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Handout No. 3
Messenger Monitoring System Machine Model_____________________________ Date___________________________ Serial Number______________________________ S.M.H.________________________ Directions: List the 5 Main Menu options in Messenger. __________ __________ Main Menu
__________ __________ __________
Directions: Use messenger to find the following parameters. 1. Engine speed __________rpms 2. Engine coolant temperature __________ 3. Fuel level__________ 4. Lifetime total reverse distance traveled__________ 5. Lifetime maximum idle time__________ 6. How many languages are offered__________ 7. What is the top gear limit_________ 8. Equipment number __________ 9. Transmission serial number__________ 10. Machine hours__________ 11. With the engine running at low idle, what is the boost pressure__________ 12. With the engine running at low idle, what is the torque converter speed__________ 13 With the engine running at low idle, what is the parking brake switch status__________ 14 With the engine running at low idle, what is the fuel filter status___________ 15 With the engine running at low idle, what is the OTG filter status__________
SERV1838 06/07
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Handout No. 4
Messenger Monitoring System (continued) Directions: Circle the correct letter indicating the best answer for each question. 1.
Which Main Menu contains the information for total fuel used? A. B. C. D. E.
2.
Which Main Menu contains the information for top gear limit? A. B. C. D. E.
3.
Performance Operator Totals Settings Service
Which Main Menu contains the information for fuel filter status? A. B. C. D. E.
5.
Performance Operator Totals Settings Service
Which Main Menu contains the information for inlet air temperature? A. B. C. D. E.
4.
Performance Operator Totals Settings Service
Performance Operator Totals Settings Service
Which Main Menu contains the information for ground speed? A. B. C. D. E.
Performance Operator Totals Settings Service
1
Transmission Sump
Screen
Transmission Pump
Pressure Tap
Bypass Switch
Main Relief Tap
Torque Converter Inlet Tap
T/C Lockup Solenoid
Temperature Sensor
2
LUC
3
Torque Converter Inlet Relief Valve
Main Relief Valve
NEUTRAL
4
To Transmission Lubrication
Cooler
Torque Converter Outlet Relief Valve
735 TRANSMISSION HYDRAULIC SYSTEM
5
6
- 222 -
Clutch Modulating Valves
6
SERV1838 06/07 Handout No. 5
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Handout No. 6
735 Power Train Testing Directions: Follow the procedure in the current testing and adjusting manuals to fill out the charts below. 1. Torque converter inlet pressure test Measurements
RPM
Specifications
RPM
Low Idle
Low Idle
High Idle
High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 2. Torque converter outlet and oil cooler inlet pressure test Measurements
RPM
Specifications
RPM
Low Idle
Low Idle
High Idle
High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 3. Transmission lubrication pressure test Measurements
RPM
Specifications
RPM
Low Idle
Low Idle
High Idle
High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 4. Transmission pump pressure test Measurements
RPM
Specifications
RPM
Low Idle
Low Idle
High Idle
High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
SERV1838 06/07
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Handout No. 7
735 Power Train Testing (continued) 5. Lockup clutch pressure test Measurements
Condition
Specifications
Lockup clutch engaged
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 6. Transmission hydraulic control system pressure test Measurements
RPM
Specifications
RPM
Low Idle
Low Idle
High Idle
High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 7. Transmission individual clutches pressure test - Use signal generator 8T-5201 to provide the transmission ECM with a hz signal through the TOS sensors. - Using the signal generator is a safe way to load the engine and see if the engine will lug under stress - Disconnect transmission lockup clutch solenoid. - Safely test clutch pressures Clutch
Measurements
RPM
Specifications
RPM
1
Low Idle
Low Idle
2
Low Idle
Low Idle
3
Low Idle
Low Idle
4
Low Idle
Low Idle
5
Low Idle
Low Idle
6
Low Idle
Low Idle
SERV1838 06/07
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Handout No. 8
735 Power Train Testing (continued) 8. Transfer gear lubrication pressure test Measurements
RPM
Specifications
RPM
Low Idle
Low Idle
High Idle
High Idle
9. Interaxle differential lock clutch pressure test Measurements
RPM
Specifications
High Idle
RPM High Idle
10. Front axle differential lock pressure test Measurements
RPM
Specifications
High Idle
RPM High Idle
11. Center axle differential lock pressure test Measurements
RPM
Specifications
High Idle
RPM High Idle
12. Rear axle differential lock pressure test Measurements
RPM High Idle
Specifications
RPM High Idle
Transmission Pump
Pilot Oil Pressure
Pump Pressure
Oil Filter
Rotary Actuator
Downshift Pressure
Selector Valve Group
Rotary Selector Spool
Upshift Pressure
D
2
1
Lockup Clutch Valve From Lockup Clutch Valve Solenoid
C
B
A
3
7 Pressure Control Group
6
4
5
H
G
F
E
- 226 -
Torque Converter Inlet Relief Valve
Relief Valve
Priority Reduction Valve
Neutralizer Valve
Downshift Upshift Solenoid Solenoid
NEUTRAL
TRANSMISSION HYDRAULIC SYSTEM
SERV1838 06/07 Handout No. 9
SERV1838 06/07
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Handout No. 10
740 Power Train Testing Directions: Follow the procedure in the current testing and adjusting manuals to fill out the charts below. 1. Torque converter lockup clutch pilot pressure test Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 2. Torque converter lockup clutch initial pressure test Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 3. Torque converter lockup clutch maximum pressure test Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 4. Torque converter inlet pressure test Measurements
RPM
Specifications
RPM
Low Idle
Low Idle
High Idle
High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
SERV1838 06/07
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Handout No. 11
740 Power Train Testing (continued) 5. Transmission hydraulic control system pressure test Measurements
RPM
Specifications
RPM
Low Idle
Low Idle
High Idle
High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
6. Transmission hydraulic control pilot pressure test Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
7. Transmission upshift pressure test Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 8. Transmission downshift pressure test Measurements
RPM Low Idle
Specifications
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
SERV1838 06/07
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Handout No. 12
740 Power Train Testing (continued) 9. Transfer gear lubrication pressure test Measurements
RPM
Specifications
RPM
Low Idle
Low Idle
High Idle
High Idle
10. Interaxle differential lock clutch pressure test Measurements
RPM
Specifications
High Idle
RPM High Idle
11. Front axle differential lock pressure test Measurements
RPM
Specifications
High Idle
RPM High Idle
12. Center axle differential lock pressure test Measurements
RPM
Specifications
High Idle
RPM High Idle
13. Rear axle differential lock pressure test Measurements
RPM High Idle
Specifications
RPM High Idle
1
3 and 7
1 and 7
2 and 6
1 and 6
3 and 6
1 and 5
3 and 5
1 and 4
3 and 4
N
R2
R1
1
2
3
4
5
6
7
Spec
Actual
A No. 3 Spec Actual
B No. 1 Spec Actual
C No. 2 Spec Actual
E No. 5 Spec Actual
F No. 4 Spec Actual
G No. 6 Spec
Actual
H No. 7
- 230 -
NOTE: Station D (lockup clutch) not used
Engaged Clutches
Gear
Station and Clutch
Initial Individual Clutch Pressures (740 Power train)
SERV1838 06/07 Handout No. 13
1
3 and 7
1 and 7
2 and 6
1 and 6
3 and 6
1 and 5
3 and 5
1 and 4
3 and 4
N
R2
R1
1
2
3
4
5
6
7
Spec
Actual
A No. 3 Spec Actual
B No. 1 Spec Actual
C No. 2 Spec Actual
E No. 5 Spec Actual
F No. 4 Spec
Actual
G No. 6
Spec
Actual
H No. 7
- 231 -
NOTE: Station D (lockup clutch) not used
Engaged Clutches
Gear
Station and Clutch
Maximum Individual Clutch Pressures (740 Power Train)
SERV1838 06/07 Handout No. 14
Steering and Fan Hydraulic Tank
Transmission Pump Drive
Cutoff Spool
Steering Pump
Margin Spool
Steering Pressure Switch
M
Secondary Steering Pump
Steering Combiner Manifold
HOLD
STEERING SYSTEM
HMU Steering Pump
Crossover Relief Valves
Steering Cylinders
Tractor
Trailer
SERV1838 06/07 - 232 Handout No. 15
SERV1838 06/07
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Handout No. 16
735/740 Steering System Testing Directions: Follow the procedure in the current testing and adjusting manuals to fill out the charts below. 1. Steering system pressure test Measurements
RPM
Specifications
High Idle
RPM High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 2. Margin pressure test Measurements
RPM
Specifications
High Idle
RPM High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 3. Standby pressure test Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 4. Case drain pressure test Measurements
RPM Low Idle
Specifications
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
SERV1838 06/07
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Handout No. 17
735/740 Steering System Testing (continued) 5. Load sensing pressure test Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 6. Secondary steering maximum pressure test Measurements
RPM Low Idle
Specifications
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
Engine
Hoist and Brake Hydraulic Tank
Brake Pump
Transmission Pump Drive
Cooling Relief Valve
To Brake Cooling
Hoist Pump
Check and Pressure Reducing Valve Manifold
To Service Brake Valve
To Service Brake Valve
Main Relief Valve
Brake System Relief Valve
HOLD
Raise Pilot Actuator
Lower Pilot Actuator
HOIST CONTROL SYSTEM
Hoist Control Valve
Manual Lowering Valve
Pilot Reducing Valve
- 235 -
Hoist Cylinder
Relief Valve
Tailgate Cylinder
Hoist Cylinder
To Parking Brake Valve
Brake Oil Pressure Switch
SERV1838 06/07 Handout No. 18
Engine
Brake Pump
To Brake Cooling
Hoist Pump
Transmission Pump Drive
Cooling Relief Valve
Main Relief Valve
Extend Pilot Control Actuator
Retract Pilot Control Actuator
To Service Brake Valve
To Service Brake Valve
Brake System Relief Valve
Ejector Control Valve
Line Relief Valve
Brake / Pilot Manifold
HOLD
Flow Regulator
3:1 Load Control
Ejector Manifold
Line Relief Valve
Orifice
Check Valve
Flow Regulator
8:1 Load Control
- 236 -
Tailgate Cylinders
Diverter Valve
Check Valve
Sequence Valve
Diverter Valve
Sequence Valve
Ejector Cylinder
EJECTOR HYDRAULIC SYSTEM
Pilot Reducing Valve
To Parking Brake Valve
Brake Oil Pressure Switch
SERV1838 06/07 Handout No. 19
SERV1838 06/07
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Handout No. 20
735/740 Hoist System Testing Directions: Follow the procedure in the current testing and adjusting manuals to fill out the charts below. 1. Pilot system pressure test Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 2. Dump body system pressure test (Raise) Measurements
RPM
Specifications
High Idle
RPM High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 3. Dump body system pressure test (Lower) Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 4. Ejector system pressure test (Eject) Measurements
RPM High Idle
Specifications
RPM High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
SERV1838 06/07
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Handout No. 21
735/740 Hoist System Testing 5. Ejector system pressure test (Retract) Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________ 6. Ejector system pressure test (Crossover) Measurements
RPM Low Idle
Specifications
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
Front Service Brake
Front Service Brake
BRAKE HYDRAULIC SYSTEM
Front Brake Temp Sensor
From Hoist Valve
Relief Valve
Hoist and Brake Hydraulic Tank
Brake Pump
Pilot Reducing Valve
Parking Brake Actuator
Rear Service Brakes
Parking Brake Control Valve
Parking Brake Pressure Switch
Rear Brake Temp Sensor
Parking Brake Accumulator Brake Oil Pressure Switch
To Hoist Pilot Valves
Check and Pressure Reducing Valve
Service Brake Accumulators
Engine
Service Brake Control Valve
SERVICE BRAKES RELEASED / PARKING BRAKE ENGAGED
SERV1838 06/07 - 239 Handout No. 22
SERV1838 06/07
- 240 -
Handout No. 23
735/740 Brake System Testing Directions: Follow the procedure in the current testing and adjusting manuals to fill out the charts below. 1. Brake system pressure test Measurements
RPM
Specifications
RPM
Low Idle
Low Idle
High Idle
High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
2. Brake line pressure test (front axle) Brakes
Measurement
RPM
Specification
RPM
Applied
Low Idle
Low Idle
Released
Low Idle
Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
3. Brake line pressure test (rear axle) Brakes
Measurement
RPM
Specification
RPM
Applied
Low Idle
Low Idle
Released
Low Idle
Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
SERV1838 06/07
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Handout No. 24
735/740 Brake System Testing (continued) 4. Parking brake accumulator pressure test Measurements
RPM
Specifications
Low Idle
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
5. Parking brake release pressure test Measurements
RPM Low Idle
Specifications
RPM Low Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
ATAAC Pump
Fuel Transfer Pump
Engine
From HMU
Relief Valve
Fan Motor
ATAAC FAN HYDRAULIC SYSTEM Fan Pump (735) Transmission
Steering Pump
Cooler
Steering and Fan Hydraulic Tank
Fan Pump (740)
Fan Motor
Bypass Valve
Fan Solenoid
COOLING FAN HYDRAULIC SYSTEM
SERV1838 06/07 - 242 Handout No. 25
SERV1838 06/07
- 243 -
Handout No. 26
735/740 Fan System Testing Directions: Follow the procedure in the current testing and adjusting manuals to fill out the charts below. 1. ATAAC fan pressure and speed test Parameter
Measurement
RPM
Specification
RPM
Pressure
High Idle
High Idle
Speed
High Idle
High Idle
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
2. Cooling fan speed test Speed
Measurement
RPM
Specification
RPM
Minimum
Low Idle
Low Idle
Maximum
1700
1700
What component does this test check? ____________________________________________ Why is this important to check? _________________________________________________
