Subaru 2002 Impreza Service Manual page 254

TRANSMISSION CONTROL MODULE (TCM)
Automatic Transmission
2. TURBO MODEL
The drive power distribution system includes a valve body attached to the side of the extension
case through a gasket and separator plate.
The pressurized fluids for the drive power distribution system (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 pilot pressure created by passing through the pilot valve in the transmission's hydraulic con-
trol assembly is further regulated into the transfer pressure 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 driving conditions.
0
The transfer pressure thus created 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
kansfer control valve and becomes the transfer clutch pressure.
0
The transfer clutch pressure is applied to the multi-plate clutch (LSD) and engages the clutch
to a controlled degree.
In this way, the degree of multi-plate clutch engagement is varied so that optimum torque is distrib-
uted to the rear wheels.
AT-32