Description & Operation

The FA4A-EL are 4-speed transaxle assemblies controlled by both electronic and mechanical systems. On Spectra, input signals from sensors are sent to the Transmission Control Module (TCM).

The PCM and TCM have built-in self-diagnosis, fail-safe mode and warning code display for the main input sensors and solenoid valves.

The valve body has 5 solenoids: 3 shift solenoids, an Electronic Pressure Control (EPC) solenoid and a Torque Converter Clutch (TCC) solenoid. Shift solenoid valves actuate shifting and TCC solenoid actuates torque converter lock-up by switching oil flow through passages in the valve body.

When TCC solenoid is switched on, fluid pressure holding the lock-up control valve is drained, allowing valve to open. When valve opens, hydraulic pressure from the rear chamber causes the converter clutch to press tightly against the converter cover. Lock-up occurs and force is transmitted directly to the transaxle with no fluid slippage.

When the PCM or TCM switches TCC solenoid off, hydraulic pressure in the front chamber becomes greater than pressure in the rear chamber. The converter clutch then moves away from the converter cover and lock-up is released.