Automatic Transmission/Transaxle: Description and Operation

GENERAL DESCRIPTION



The A540E is a 4-speed, Electronically Controlled Transaxle developed exclusively for use with transversely- mounted engines. A lock-up is built into the torque converter clutch. The A540E transaxle is mainly composed of a torque converter clutch, a 4-speed planetary gear unit, a differential, a hydraulic control system and an electronic control system.

GENERAL SPECIFICATION





OPERATION









1. FUNCTION OF COMPONENTS



Power from the engine transmitted to the input shaft via the torque converter clutch is then transmitted to the planetary gears by the operation of the clutch. By operation of the brake and one-way clutch, either the planetary carrier or the planetary sun gear are immobilized, altering the speed of revolution of the planetary gear unit. Shift change is carried out by altering the combination of clutch and brake operation. Each clutch and brake operates by hydraulic pressure; gear position is decided according to throttle opening angle and vehicle speed, and shift change automatically occurs. The conditions of operation for each gear position are shown on the following illustrations:


2. HYDRAULIC CONTROL SYSTEM



The hydraulic control system is composed of the oil pump, the valve body, the solenoid valves, the accumulators, the clutches and brakes as well as the fluid passages which connect all of these components.
Based on the hydraulic pressure created by the oil pump, the hydraulic control system governs the hydraulic pressure acting on the torque converter clutch, clutches and brakes in accordance with the vehicle driving conditions.
These are three solenoid valves on the valve body.
The No. 1 and No.2 solenoid valves are turned on and off by signals from ECM to operate the shift valves and change the gear shift position.
The No.3 solenoid valve is operated by signals from the ECM to engage or disengage the lockup clutch of the torque converter clutch.