Subaru XT 1988 Service Manual page 540

3-2
AUTOMATIC TRANSMISSION AND DIFFERENTIAL
2) FUNCTION OF EACH VALVE
Name
• Pressure regulator valve
• Pressure regulator plug
• Pressure regulator sleeve plug
Pressure modifier valve
Pressure modifier accumulator
piston
Pilot valve
• Accumulator control plug
• Accumulator control sleeve
Manual valve
Shift valve A
Shift valve B
Shuttle shift valve S
Overrunning clutch control valve
Function
Regulates the pressure of oil delivered from the oil pump to an optimum level (line
pressure) corresponding to vehicle running conditions.
An auxiliary valve for the pressure regulator valve. This valve adjusts pressure used
to regulate I ine pressure to an optimum level corresponding to running conditions.
Smoothes the pressure regulated by the pressure modifier valve to prevent pulsation
in line pressure.
Creates the constant pressure (pilot pressure) necessary to control line pressure,
lock-up, overrunning clutch, 3-2 timing, and gearshift operations from line pressure.
Adjusts accumulator back pressure to correspond to running conditions.
Delivers line pressure to each circuit corresponding to the selected position.
~ircuit
CD CV ®
Range~
P
R
o
N
o
o
3
o
2
o o
PRND32
, !
I'
I I
B)
Fig. 42
L3-924
When the valve is set in the "line pressure no delivery" position, the pressure is
relieved.
Simultaneously changes three different oil passages using shift solenoid 1 output
pressure corresponding to such operating conditions as vehicle speed and throttle
opening. Combined with shift valve B, this valve permits automatic shifting of
1 st
~
2nd
~
3rd
::t
4th speeds.
Simultaneously changes three different oil passages using shift solenoid 2 output
pressure corresponding to such operating conditions as vehicle speed and throttle
opening. Combined with shift valve A, this valve permits automatic shifting of
1 st
~
2nd
~
3rd
t:
4th speeds.
Changes the 3-2 timing control and overrunning clutch control oil passages corre-
sponding to the throttle opening. When the throttle is wide open, the overrunning
clutch becomes inoperative to prevent interlocking at 4th speed.
Changes oil passages so as to prevent simultaneous operation of the overrunning
clutch when the brake band is actuated at 4th speed. (Operation of overrunning
clutch at 04 speed results in interlocking.)
26