ELECTRICAL COMPONENTS SHIFT SOLENOID VALVES The Hydra-matic 4L80-E uses two electronic shift solenoid va lves (1-2 and 2-3) to control upshifts and downshifts in all forward gear ranges. These shift solenoid valves work together in a combination of ON and OFF sequences to control the various shift valves. The PCM uses numerous inputs inputs (as shown in Figure 39) to determine which solenoid state combination the transmission should be in. The following table shows the solenoid state combination required for each gear range: GEAR RANGE Park, Reverse, Neutral First Second Third Fourth
1-2 SOLENOID ON ON OFF OFF ON
O-RING
SOLENOID FLUID
➤
FILT ACTR FD
X E
2-3 SIGNAL
➤
FILT ACTR FD
1-2 SIGNAL
R D 3 X 2 E
X E
➤
➤
2-3 SIGNAL
D F R T C A
G I S 3 2 ➤
G I S 3 2
N.O.
D F L C 3 N R P
1 2 D
2-3 SOL EX
D F L L X E C C F I H H T T R 4 4 O
OFF
D F R T C A
FILT ACTR FD
G I S 2 1
N.O.
➤
➤
L A N G I S 2 1
1-2 SIGNAL
OFF
2-3 SIGNAL
R D 3 X 2 E
X E D C F R O
D F R T C A
G I S 3 2
G I S 3 2
2-3 SHIFT S HIFT VALVE VALVE X A 4 D F E B D L F N C R P 4
1 2 D
2-3 SOL EX N.O.
D F L C 3 N R P
1-2 SIGNAL
D F L L X E C C F I H H T T R 4 4 O
ON
D F R T C A
➤
L A N G I S 2 1
R D 3 X 2 E
X E D C F R O
D F R T C A
G I S 3 2
G I S 3 2
➤
2-3 S HIFT VALVE VALVE X A 4 D F E B D L F N C R P 4
Figure 40
➤
➤
2-3 SOL ➤
EX
ON
N.O.
D F L C 3 N R P
3-4 SHIFT
THIRD GEAR
➤
➤
➤
➤
➤
ON
N.O.
➤
FILT ACTR FD
➤
EX
➤
X E
➤
➤
➤
➤
3-4 SHIFT
PARK/ REVERSE/ NEUTRAL/ FIRST GEAR
1-2 SOL
1-2 SHIFT VALVE VALVE
EX
➤
➤
➤
E V D I F R E R D V T V V V 3 I C E E E - R A R R R 2 D
➤
FILT ACTR FD
2-3 S HIFT VALVE VALVE X A 4 D F E B D L F N C R P 4
ON
➤
X E D C F R O
FRAME
1-2 SOL
1-2 SHIFT VALVE VALVE
EX
➤
FILT ACTR FD
1 2 D
➤
COIL ASSEMBLY
EXHAUST
G I S 2 1
1-2 SOL
➤
FILTER
When the 2-3 SS valve is energized (ON), 2-3 signal fluid is blocked from exhausting through the solenoid, thereby creating high 2-3 signal fluid pressure (see Third Gear and Fourth Gear examples below). High 2-3 signal fluid fluid pressure acts on the 2-3 2-3 shift valve to move it into the upshifted position (against spring force and actuator actuator feed fluid fluid pressure). However, in Manual Second and Manual First gear ranges, D21 fluid pressure keeps the 2-3 shift valve in the downshifted position regardless of the 2-3 SS valve state. High 2-3 signal fluid fluid pressure also assists spring force and actuator feed fluid pressure at the 1-2 shift valve to keep the valve in the ups hifted position when 1-2 signal fluid pressure is either high or low.
E V D I F R E R D V T V V V 3 I C E E E - R A R R R 2 D
G I S 2 1
N.O.
CONNECTOR
2-3 Shift Solenoid (SS) Valve (311): The 2-3 SS valve functions similar to the 1-2 SS valve in that the PCM controls the path to ground for the electrical circuit to turn the solenoid ON or OFF. Filtered actuator feed fluid feeds the 2-3 signal fluid circuit circuit at the 2-3 shift valve (312). (312). When the 2-3 SS valve is de-energized (OFF), 2-3 signal fluid exhausts through the solenoid, thereby creating low pressure in the 2-3 signal circuit (see Park/Reverse/Neutral/First Gear example below). Similar to the 1-2 signal signal circuit, fluid remains in the 23 signal circuit with the 2-3 SS valve de-energized (OFF), only at a low pressure due to the exhaust through the solenoid. Low pressure is shown by light blue fluid color while high 2-3 signal fluid pressure is shown as dark blue fluid color.
When the 1-2 SS valve is energized (ON), 1-2 signal fluid is blocked from exhausting through the solenoid, thereby creating high 1-2 signal fluid pressure (see Park/Reverse/Neutral/First Gear and Fourth Gear examples below). High 1-2 signal fluid fluid pressure acts on the 1-2 shift valve to keep it in the downshifted position (against spring force and actuator feed fluid pressure) when 2-3 signal fluid pressure is low. High 1-2 signal fluid pressure also acts on the 3-4 shift valve (308) to keep it in the upshifted position (against spring force and actuator feed fluid pressure) in the absence of PRN fluid pressure.
➤
PLUNGER
SHIFT SOLENOID VALVE (OFF)
1-2 Shift Solenoid (SS) Valve (313): Filtered actuator feed fluid feeds the 1-2 signal fluid circuit at the 1-2 shift valve (314). When the 1-2 SS valve is de-energized (OFF), 1-2 signal fluid exhausts through the solenoid, thereby creating low pressure in the 1-2 signal circuit (see Third Gear example below). Even with the solenoid de-energized, de-energized, fluid remains in the 1-2 signal fluid circuit but at low pressure because filtered actuator feed fluid continues continues to feed the circuit. Low pressure is shown by light blue fluid color while high 1-2 signal fluid pressure is shown as dark blue fluid color.
1-2 SHIFT VALVE VALVE
S PRING
2-3 SOLENOID OFF OFF OFF ON ON
The shift solenoid valves are de-energized (turned OFF) when the PCM opens the path to ground for the solenoid’ solenoid ’s electrical circuit. With the solenoid OFF, signal fluid pressure moves the metering ball and plunger away from the metering ball’ ball ’s seat. This allows signal fluid to flow past the metering ball and exhaust out of the solenoid as shown in the illustration. When the PCM provides a path to ground for the electrical circuit to energize (turn ON) the solenoid, current flows through the coil assembly in the solenoid and creates a magnetic field. The magnetic field moves the plunger to the left (with respect to the illustration) and seats the metering ball, thereby blocking the exhaust passage and causing signal fluid pressure to increase.
E V D I F R E R D V T V V V 3 I C E E E - R A R R R 2 D
