Description & Operation
The CD4E is a 4-speed transaxle assembly. The CD4E is controlled by both electronic and mechanical systems utilizing a compound planetary gearset, chain drive, final drive planetary gearset and an open differential. One band, 5 friction clutches, and 2 one-way clutches provide 4 forward gear ratios and reverse. See Fig 1.
Input signals 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.
Five electronic solenoids accomplish the following functions:
- 2 On/Off solenoids for shifting.
- One Pulse-Width Modulator (PWM) 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.