Overhaul - 42LE Automatic Transmission: Description

The 42LE is an electronically controlled 4-speed transaxle. Transaxle uses hydraulically operated clutches controlled by Transaxle Control Module (TCM). Transaxle consists of 3 multiple-disc input clutches, 2 multiple-disc holding clutches, 4 hydraulic accumulators and 2 planetary gear sets to provide 4 forward speeds and reverse. See Figure .

TCM receives information from various sensors and controls the solenoid assembly through the transaxle control relay. Solenoid assembly consists of 4 solenoids for controlling hydraulic pressure to 4 of the 5 transaxle clutches.

TCM contains an adaptive memory which learns application and release rates of transaxle components for smooth operation. TCM also learns rate at which applied elements build pressure sufficient for a speed change. Adaptive control can adapt to altitude, temperature, engine output, etc.

CAUTION: If battery is disconnected or voltage supply to TCM is interrupted, TCM must relearn shift characteristics. If TCM, transaxle internal components, solenoid assembly or torque converter are replaced, TCM will have to relearn shift characteristics. Perform shift quality quick-learn procedure. See SHIFT QUALITY QUICK-LEARN PROCEDURE in CHRYSLER 42LE ELECTRONIC CONTROLS article.

CAUTION: If TCM is replaced or changed from one vehicle to another, proper procedure must be followed to calibrate TCM for different equipment combinations to provide speedometer operation and correct readings. Failure to perform this procedure will result in no speedometer operation. See PINION FACTOR PROCEDURE in CHRYSLER 42LE ELECTRONIC CONTROLS article.