Subaru LEGACY 2002 Quick Reference Index page 278

GENERAL
Automatic Transmission
1. General
A: OUTLINE
The automatic transmission comes in two types; one is for the models without a variable torque
distribution (VTD) system (called "MPT models" – standing for multi-plate transfer models – in the
following description), and the other for the models with a VTD system (called "VTD models" in the
following description). Both the types are of a full-time all-wheel drive design, combining the torque
converter/clutch section, final reduction section, automatic transmission section, and transfer sec-
tion into a single unit (see "C: CROSS SECTIONAL VIEW").
These transmissions are controlled electronically by the transmission control module (TCM). The
TCM is a microprocessor-based unit that controls operation of various solenoid valves and other
electric devices depending on many variables (throttle opening, vehicle speed, engine speed, se-
lected gear range, etc.) to select the optimum gear and the most appropriate way of power trans-
mission (including engine braking and lock-up clutch engagement) for a particular condition.
The TCM has an additional function of automatically selecting either of the two control patterns
("Base" and "Power") in accordance with the driving type which it identifies from the rate of move-
ment of the accelerator pedal. It uses the Base pattern typically for cruising on a flat road and the
Power pattern during acceleration or up-hill driving.
AT-2