Subaru XT 1988 Service Manual page 547

AUTOMATIC TRANSMISSION AND DIFFERENTIAL
3-2
(8) Overrunning Clutch Control Valve
During coasting, no oil flows into passage
@,
and the valve
is set to condition (b) by spring force. Oil from passage
@
exerts pressure on the overrunning clutch via the overrunning
clutch reducing valve from passage
®.
Under conditions other than coasting, oil flows into passage
@,
and the valve is set in condition (a). In 4th speed, the oil
from passage
CD
exerts pressure on the servo 4A chamber via
passage
®.
1 st reducing
(a)
(b)
"D" range pressure
4A pressure
To overrunning
clutch reducing valve
Pilot pressure or overrunning
clutch solenoid pressure
OV/C
4A
To overrunning clutch reducing valve
1st
(Force of 1st
L
reducing pressure)
,..-------11-----+--.
F s - - - - + I
(Spring force)
Fig. 50
(9) Overrunning Clutch Reducing Valve
"0" range
Oil from the overrunn ing clutch control valve to passage
®
exerts the overrunning clutch pressure to chamber
CD
via
orifice
@,
and pushes the valve to the right. If overrunning
clutch pressure exceeds spring force, the valve moves further
to the right. This releases the overrunning clutch pressure. As
a result, overrunning clutch pressure is maintained at a con-
stant level.
"3" range
In addition to the forces mentioned above, the valve is also
pushed to the left by the force of oil coming from the manual
valve into the chamber
®.
Accordingly, overrunning clutch
pressure is adjusted at a higher level than that of "D" range.
From shift
valve B
FOVR/C REC
x.
(Force of overrunning
clutch reducing
pressure)
(Force of pilot pressure)
Fp
FOVR/CSOL
(Force of overrunning clutch
solenoid pressure)
"D" range pressure
(From manual valve)
L3-926
"3" range pressure
L _ _ _ _
..;:;.-=~_To overrunning clutch
"0" range pressure
P L ("3" range pressure)
_ - - - Fs (Spring force)
To overrunning clutch
L3-633
Fig. 51
33