Overhaul - 4R44E: Description

The 4R44E is an electronically controlled 4-speed automatic transmission. This transmission features a 4-element torque converter with Torque Converter Clutch (TCC), 3 compound planetary gear sets, 3 clutch bands, 3 multi-plate clutches and 2 one-way clutches. The Powertrain Control Module (PCM) controls TCC using a pulse-width modulated TCC solenoid.

Shift control solenoids control gear selection and are operated by the EEC-V system. For additional information on the EEC-V system, refer to appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.

Input signal from sensors are sent to the Powertrain Control Module (PCM). The PCM can determine when the time and conditions are right for a shift or converter clutch application. The PCM can also determine line pressure needed to optimize shift feel. Six electronic solenoids accomplish the following functions:

• 3 On/Off solenoids for shifting.
• One pulse-width modulator solenoid for Torque Converter Clutch (TCC) control.
• One Electronic Pressure Control (EPC) solenoid for line pressure control.
• One 3-2 timing/coast clutch solenoid to control release of coast clutch, coordinated release of the direct clutch, and apply of the low and intermediate band.

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