General

4EAT Transmission:

GENERAL
This system utilizes a microcomputer for accurate control of vehicle speed, engine brake operation, lock-up operation, gear shift timeing and other functions. It corresponds to the throttle opening, actual vehicle speed, engine rpm and range position signal. Further, this system adopts an electronically controlled full-time all wheel drive (AWD) system.

The AWD system has a transfer hydraulic pressure control unit incorporating a duty solenoid and a multi-plate transfer (MPT) consisting of a wet type multi-plate clutch on the rear of the automatic transmission section. The control unit stores optimum transfer clutch torque (duty ration) data from for various driving conditions. When actual driving conditions (vehicle speed, throttle position, gear range, wheel slip, etc.) are detected by various sensors, the control unit selects the most suitable duty ratio from memory, and controls the transmitting torque of the transfer clutch by means of the hydraulic presure controlling solenoid.

FEATURES
1. Two one-way clutches and four accumulators are used to reduce gear shift shock and gear select shock, and fully electronic control from 1st to 4th speeds, hydraulic oil pressure (line pressure), lock-up operation, etc.
2. A hydraulic lock-up type torque convertor, variable delivery oil pump, gear train with two sets of simple planetary gears (permitting four forward and one reverse stage) are used to improve driving dynamics and fuel economy.
3. A push-pull cable featuring less vibration to the high rigid transmission case and control unit is used for improved quietness during driving.
4. The transfer clutch capacity can be accurately controlled by means of the electronic control system. This is especially effective for eliminating tight corner braking phenomenon which occur at low speeds, thereby achieving smooth driving.
5. An optimum rear wheel drive distribution is achieved which corresponds to engine output and gear shift position and improves fuel economy and steering stability.
6. For vehicles with ABS, the braking performance is improved by the control of the clutch and gear locking at a particular shift position through ABS operation-time control.