SERVO APPLY VALVE (1992 DESIGN, 1993 AND 1994)
Figure 48
SERVO APPLY VALVE
REV
FROM MAN
V
AL
VE
REV
EX
1,3,4
TO FWD/REV SERVO PISTON
The servo apply valve, located in the valvebody is used to
control reverse apply oil to the forward/reverse servo
piston. When reverse is selected, the manual valve will
allow oil to be applied to the servo apply valve. If vehicle
speed input to the PCM indicates the vehicle is less than 8
km/h (5 mph), then the dog clutch can be moved to the
reverse direction without causing damage. With the
vehicle speed less than 8 km/h (5 mph), and reverse
selected, the PCM will command high-line pressure.
When high-line pressure is commanded, the pressure will
move the servo apply valve against the spring which opens
up the passage allowing oil to pass through the servo apply
valve to the forward/reverse servo piston.
If reverse is selected when vehicle speed is greater than 8
km (5 mph), the PCM will command low-line pressure
causing the servo apply spring to keep the passage in the
servo apply valve closed, preventing oil to reach the
forward/reverse servo piston. This action does not allow
the dog clutch to move, thus preventing internal damage to
the transaxle.
NOTE: The Servo Apply Valve shown here was not used
in the 1991 and 1992 1st design valve body.
35
AUTOMATIC TRANSMISSION SERVICE GROUP
Technical Service Information