Transaxle Description

Transaxle Description





The 4F20E is an electronically controlled automatic transaxle that uses a combination of hydraulic and electronic systems to control transaxle forward gear shifting and torque converter lockup. The transaxle has the following main components:
- Reverse clutch
- 3-4 Clutch
- Forward and coasting clutch
- Low/reverse clutch
- Low one-way clutch (roller)
- 2-4 Band
- Two planetary gear sets

Identification Tags





The transaxle identification tag is located on the transaxle side cover. The tag provides transaxle serial number, application year, and an identification code.

Range Selection





The Villager transaxle has six range positions: P, R, N, D, 2, and 1. Overdrive is manually controlled by a dash mounted switch.

Park
There is no powerflow through the transaxle in the Park position. The parking pawl locks the output shaft to the transaxle case. The vehicle can be started in Park and the Park position must be selected in order to remove the ignition key.

Reverse
The Reverse gear enables the vehicle to operate at a reduced ratio in a rearward direction. There is engine braking in Reverse.

Neutral
There is no powerflow through the transaxle in Neutral. The engine can be started in Neutral, but the ignition key cannot be removed until shifted into Park.

Drive
Drive is the normal gearshift lever position for most forward driving conditions. This position provides all automatic shifting, application and release of the torque converter clutch, and maximum fuel economy during normal operation. When Overdrive is turned off, the vehicle will shift up to Third Gear. There is engine braking in Third Gear when Overdrive is turned off.

Second Gear
The Second Gear position allows the transaxle to shift up to Second Gear only. Engine braking occurs in Second Gear, making this position useful on steep grades.

First Gear
Selection of the First Gear position at idle will allow only First Gear operation (no upshifts). If this position is selected at normal road speeds, the transaxle will first downshift into Second Gear, then downshift into First Gear when vehicle speed falls below approximately 45 km/h (28 mph). First Gear engages the low/reverse clutch for greater power handling ability. There is engine braking in the First Gear position.

Shift Patterns
Upshifts
Upshifts are controlled by the Transaxle Control Module (TCM). The TCM receives input from the PCM, Output Shaft Speed sensor (OSS), Throttle Position Sensor (TPS), Transmission Fluid Temperature (TFT) Sensor, and vehicle rpm to determine the optimal upshift points. Torque Converter Clutch (TCC) operation and shift feel are also determined by the TCM.

Downshifts
Under certain conditions, the transaxle will automatically downshift to a lower gear range without manual movement of the shifter lever. There are three categories of automatic downshifts: coastdown, torque demand, and forced (kickdown) shifts.

Coastdown
The coastdown downshift occurs as the vehicle is coasting down to a stop. The transaxle automatically downshifts to match gear range to vehicle speed.

Torque Demand
The torque demand downshift occurs automatically during part throttle acceleration when the demand for torque is greater than the engine can provide at that gear ratio. If applied, the transmission will disengage the TCC to provide added acceleration.

Kickdown
For maximum acceleration, the driver can force a downshift by pressing the accelerator pedal to the floor. A forced downshift into a lower gear is possible below calibrated speeds.