Subaru XT 1988 Service Manual page 548

3-2 AUTOMATIC TRANSMISSION AND DIFFERENTIAL
(10) Shuttle Shift Valve S
"0", "3" range
The valve is pushed to the right by spring force, and is pushed
to the left by the "D" and "3" range pressure.
When the throttle opening is small (Fs> F
D ),
the valve is set
in condition (a). Overrunning clutch solenoid pressure (shift
solenoid 3 pressure) from passage ® is then appl ied to the
overrunning clutch control valve via passage
®.
Engagement
of the overrunning clutch is controlled by this pressure.
When the throttle opening is large (Fs
<
F
D ),
the valve is set
in condition (b). Accordingly, pilot pressure from passage
CD
is applied to the overrunning clutch control valve via passage
® .
This pressure prevents the overrunning clutch from engag-
ing. The oil coming from passage ® exerts pressure on the
3-2 timing valve via passage ® .
"2" range
The "2" range pressure is applied to the valve, setting the valve
in condition (a). In this state, engagement of the overrunning
clutch can be controlled by the overrunning clutch solenoid
pressure (shift solenoid 3 pressure).
(a)
(b)
(Spring force)
Fs
FII
(Force of "2"
To overrunning clutch
control valve
To 3-2 timing valve
pressure
Overrunning
clutch
pressure
Pilot
pressure
(From manual valve)
FD [Force of "D",
pressure,
condition (b)]
range pressu re)
'-----+----+---t--'
Fig. 52
3-2 timing
valve
Overrunning
clutch control
valve
L3-927
34
(11) Pilot Valve
The valve is pushed to the right by pilot pressure, and is
pushed to the left by spring force. If pilot pressure force
exceeds spring force, the valve moves to the right, and pilot
pressure is released. Accordingly, pilot pressure is maintained
at a constant level.
Li ne pressu re
Line pressure
Fp (Force of
pilot pressure)
-
Fs (Spring pressure)
-
L3-635
Fig. 53
(12) Manual Valve
Rotary motion of the range select lever is changed into re-
ciprocating motion of the manual valve by the manual lever.
In "P", "R", "N", "D", "3", and "2" positions, the manual
valve is set respectively so that line pressure ® is distributed
to the following line pressure circuits:
"P" range:
Line pressure ® - @ - d r a i n
"R" range:
Line pressure
®-®~
reverse clutch
L-
low & reverse brake
"N" range:
Line pressure ®
- - - - - - - - - 0 _ _
None