DSG

Technically Speaking

Subject: Valve-body components and operation

Unit: VW DSG 02E

Vehicle Applications:

Volkswagen’s

Direct-Shift Gearbox Part 5

2004-up New Beetle, New Jetta, Golf GTI

Essential Reading:

T

he DSG valve body is definitely one of the simplest we have seen in transmissions (see figures 1 through 5 here and on page 18). It contains only five valve lineups, two checkballs, three damper assemblies, two pressure senders (pressure sensors/transducers) and 13 filters (see figures 2, 3 and 5). The two checkballs and pressure senders are in the K1- and K2-clutch pressure circuits, which are being continues page 18

Figure1 Fig ure1

Rebuilder Shop Owner Center Manager Diagnostician R&R

Author: Wayne Colonna, ATSG Transmission Digest Technical Editor

Figure2 Fig ure2

Pressure-regulator valve

Clutch-cooling valve

Copyright © 2007 ATSG

10

Transmission Digest


continued from page 10 used for precise clutch-pressure control and release. These sensors are integral to the TCM and are staked into the channel-plate portion of the valve body (see Figure 4), making these sensors non-serviceable separately. This also means that the TCM cannot be easily removed from the valve body even if you remove all the bolts (see Figure 6 on page 20). So it appears that if a pressure sender fails, you will be buying a TCM/valve-body assembly to correct the problem.

It is no secret that the manufacturers are doing everything they can to get us to the place where all we can do is unit replacements – very un-American, in my opinion. If you prevent the middle-class working man from earning a living, you weaken a country. It is not typical of me to get on a soapbox like this, but the things we are seeing in the automotive business have me very concerned. Try to buy transmission parts for a Nissan Murano; it cannot be done. You are forced to buy a

whole transmission. Our politicians do not give a hoot about America, just their back pocket. It sure would be nice if our automotive associations had more clout on The Hill. OK, I am done; back to tech. Thank you for giving me a few minutes to blow off some steam. With the valve body as simple as it is, it does not take much effort to identify and trace hydraulic circuits, as I did in Figure 7. This becomes helpful in identifying case continues page 20

Figure4

Figure3

Valve-Body Details

Figure5

Valve-Body Details

Multiplexer valve

e v l a v y t e f a s 1 7 3 N

e v l a v y t e f a s 3 3 2 N

Hydraulic-pressure sender 1 (G193)

Hydraulic-pressure sender 2 (G194)

4.25mm ball-seat flat faces up

6mm ball


18


Transmission Digest


passages for testing. For example, if you look below the multiplexer valve in the hydraulic circuit shown in Figure 8 on page 22, the shift rails inside the transmission are represented. From left to right you have the 3-1 shift rail, the N-5, the R-6 and then the 4-6. Each end of these shift rails sits inside a cylinder containing a piston seal known as a gear actuator (see figures 9 and 10 on page 24). When

Figure6

Figure7

you look at Figure 11, you can see how one can inspect these gear actuators for leaks with compressed air through their respective case passages. You also will notice that there are slots and holes within the center of the case as shown in Figure 12. These are openings for various sensors built into the TCM, which are identified in Figure 13 on page 26. Four of those sensors are called “travel sensors.” They monitor the position of the four shift rails by reading the magnet travel senders 3 that are affixed to each of the rails (see figures 14 R and 15). The other sensors and senders identified in figN371 safety ures 13 and 15 are: solenoid & valve • The input-speed sender (G182) is a Hall-ef5 fect sensor that reads the 1 outside of the K1/K2clutch drum, which rotates N88 N88 signal Sign at engine speed. This signal is used to calculate clutch slip for a more-pre4 cise control of clutch apply N233 safety and release. In the event of solenoid & K2 K1 a failure, the redundancy valve N91 K2 K1 signal backup is an engine-speed 6 N91 Signal 4 1 5 signal, which the transmisN371 N371 D sion computer receives damper over the CAN (controller N90 signal area network) bus. N90 Signal • The multiplate-clutch oil-temperature sender (G509) is also inside the N89 signal N89 Signal 4 5 same housing as the inputN88 Signal N88 signal speed sender, and it measures the temperature of the N233 N233D damper oil as it comes from the X X X X X outlet ports in the drum 2 3 assembly. From this input, N the transmission computer R regulates the flow of clutch-cooling oil and initiates further measures to protect the gearbox. It 2 2 6 6 N N 3 3 4 4 R R 5 5 1 1 measures temperatures rapidly and works within Multiplexer Multiplexer N90 N90 N89 N89 N91 N91 N88 N88 a range from –55° C to Signal signal +180° C. As a backup Copyright © 2007 ATSG text continues page 24 2

K2-pressure Pressure sender G194 Sender G194

Pressure K1-pressure Sender senderG193 G193

Ext. cooler coolerin In

tch Cool Clutch cool Damper Cooler rdamper N218 Signal N218 signal

N217 Signal N217 signal

Pump Out Pump out Pump in

20

Transmission Digest

Technically Speaking Figure8

Hydraulic Details

PR valve

# 3 main line-pressure control solenoid N217

Press. relief valve Exhaust

Clutch-cooling-oil slide valve External cooler

External filter

# 4 cooling-pressure control solenoid N218

Gear lube spray

Exhaust

Damper piston

N371 safety solenoid & valve

Sump and internal filter N233 safety solenoid & valve

Exhaust

G194 press. sender

Exhaust

To K2 clutch

G193 press. sender To K1 clutch

N88

N89

N90

N91 K2 reg. sol. N216

K1 reg. sol. N215 Multiplexer N92

Exhaust

N88 – 1st and 5th

Multiplexer valve

N89 – 3rd and neutral N90 – 2nd and 6th N91 – 4th and reverse 3

1

N

5

R

6

4

2

First gear Copyright © 2007 ATSG

22

Transmission Digest


should this sensor fail, the transmission computer uses signals from the gear-oil temperature sensor G93 and the control-unit temperature sensor G510, both inside the transmission computer. Figure 9

• Input-shaft speed sensor 1 (G501) and input-shaft speed sensor 2 (G502) are both Hall-effect sensors inside the transmission computer. These sensors are excited by the wheel-speed sensors Figure 10

Figure11

4th-gear shift 1st-gear shift Clutch cooling circuit

To external cooler

2nd-gear shift 3rd-gear shift Pump out (to PR)

K2 clutch K1 clutch

Pump in

6th-gear shift 5th-gear shift

Reversegear shift Neutralgear shift

mounted on each shaft. These signals are used in conjunction with the input-speed signal (G182) to determine the output slip of clutches K1 and K2. Besides using these signals to tailor clutch-slip control, it also can determine whether the right gear ratio has been selected. If sender G501 fails, only second gear can be achieved. If sensor G502 fails, only 1st and 3rd can be achieved. Output-speed sensors G195 and G196 are also Hall-effect sensors inside the transmission computer. They, too, are excited by a wheelspeed sensor mounted on the shaft. By having two output-speed signals that are offset, the computer can detect direction of travel. The G195 sends a “high” signal and the G196 sends a “low” signal. As a redundancy should these sensors fail, ABS wheel-speed signals are substituted for both direction of travel and road speed. • Gear-oil temperature sender G93 and control-unit temperature sender G510 are both inside the Mechatronic transmission-control unit. With this unit being placed inside the transmission, the oil temperature can be monitored. These two sensor signals are used to check the Mechatronic’s temperature, they are used to start a warm-up program and they check each other for faults. If an over temp is detected, measures are initiated to reduce oil temperature as rapidly as possible to avoid excessive heat generation in the continues page 26 Figure 12

Molded seals are used inside each of the shift-fork cylinders


24

Transmission Digest

Technically Speaking Figure 13

Figure 14

Electrical Details Travel sensor G490

Travel sensor G489

Output-speed sensor G195 Output-speed sensor G196 Control-unit temp. sensor G510

Input-shaft sensor G502

Gear-oil temp. sensor G93 Input-shaft sensor G501

Travel sensor G488

Travel sensor G487


Figure15

Electrical Details

Output-shaft sender (G195 and G196)

Input-shaft sender 1 (G501)

Input-shaft sender 2 (G502)

Input-speed sender (G182) Multiplate-clutch oil-temperature sender (G509)

sensor sensor sensor sensor

1 2 1 1

(G487) (G488) (G489) (G490)

The Bottom Line: Tell us your opinion of this article: Circle the corresponding number on the free information card.

96 Useful information. 97 Not useful information. 98 We need more information.

Magnet travel sensors mounted on each of the four shift rails generate signals for the computer to detect the position of the gear actuators. Travel Travel Travel Travel

Mechatronic unit. At temperatures that exceed 138° C, the Mechatronic unit initiates a reduction in engine torque. Above 145° C, oil no longer is supplied to the K1 and K2 clutches, placing the transmission in neutral. This concludes the series on the DSG 02E gearbox designed to give you an idea of the type of transmissions we can expect to see more of. Its compact design and the elimination of a torque converter are quite favorable for the manufacturer. So now we have CVTs, DSGs, six-speed front- and rear-wheeldrive transmissions, AWD transmissions and, yes, there is now an eight-speed rear-wheel-drive transmission by ZF. It looks as if we could do well in the transmission business if we could buy parts. Is the right to rebuild being taken from us one transmission at a time? TD

detects detects detects detects

1st- and 3rd-gear positions 2nd- and 4th-gear positions 6th- and reverse-gear positions 5th- and neutral-gear positions

If a sensor should fail, that section of the gearbox will be isolated for non-use.


26

Transmission Digest

DSG

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