Subaru 2002 Impreza Service Manual page 252

TRANSMISSION CONTROL MODULE (TCM)
Automatic Transmission
M: TRANSFER CONTROL
The transfer hydraulic pressure control unit includes a valve body attached to the side of the exten-
sion case through a gasket and separator plate.
The pressurized fluids for the transfer hydraulic pressure control (line pressure and pilot pressure)
are supplied from the oil pump by way of the passages formed in the transmission case and then
the passages in the extension case that lead to the hydraulic circuit in the transfer valve body.
The line pressure is regulated by the transfer control valve whose opening is controlled by the
transfer pressure created by the transfer duty solenoid.
0
The transfer duty solenoid is controlled by the TCM. The TCM changes the solenoid controlling
duty ratio according to the driving conditions.
0
The transfer duty solenoid creates the transfer pressure from the pilot pressure. The transfer
pressure is applied to the transfer control valve and adjusts the valve's opening.
0
The line pressure directly led to the transfer control valve, on the other hand, is regulated by the
transfer control valve and becomes the transfer clutch pressure.
0
-The transfer clutch pressure is applied to the transfer clutch and engages the clutch to a con-
trolled degree.
In this way, the degree of transfer clutch engagement is varied so that optimum torque is distrib-
uted to the rear wheels according to vehicle driving conditions.
1. NON-TURBO MODEL
C .
AT-30