Subaru XT 1988 Service Manual page 575

AUTOMATIC TRANSMISSION AND DIFFERENTIAL
3-2
• Pilot valve (transfer)
The pilot pressure acts on the valve to force it to the right, and
the spring acts to force the valve to the left. Therefore, when
pilot pressure exceeds the force of the spring, the valve moves
to the right and drains the pilot pressure so that it does not
exceed the fixed level.
Fp
(Pilot pressure)
Line pressure
Line pressure
Pilot pressure
Fig.
86
Fs
(Force of spring)
L3-663
61
• Transfer control valve
The duty pressure, which is controlled by pulse amplitude
modulation by duty solenoid C, acts on the valve as a force
pressing it to the right. On the other hand, oil entering from
the oil passage
CD
flows through the throttle inside the valve
into the oil chamber
®,
where it acts as a force pressing the
valve to the left together with the spring. Therefore, oil
entering from the oil passage
CD
is regulated so as to be
balanced by the forces acting in both directions and becomes
the transfer clutch control oil pressure.
D
Transfer clutch pressure
x
Line pressure
F T/F SOL
(Duty pressure
controlled by
duty solenoid C ) , L . - - - - - + - - - - - - '
To transfer clutch
Fig_ 87
Line pressu re
Fs
(Force of transfer
clutch pressure)
L3-664