Transmission Fluid Temperature (TFT) Sensor
This sensor is located on the transaxle main control body. It is a temperature-sensitive device called a thermistor. The resistance value of the transmission fluid temperature (TFT) sensor will vary with temperature change. The PCM monitors the voltage across the TFT to determine the temperature of the transmission fluid.
The PCM uses this initial signal to determine whether a cold start shift schedule is necessary. The cold start shift schedule allows quicker shifts when the transmission fluid temperature is cold. The PCM also inhibits torque converter clutch operation at low transmission fluid temperatures. Corrects EPC pressures for temperature.
Check Fluid Level and Condition
| CAUTION | The vehicle should not be driven if the fluid level indicator shows the fluid below the DO NOT DRIVE mark or internal failure could result. |
If the vehicle has been operated for an extended period of time at highway speeds, in city traffic, in hot weather or while pulling a trailer, the fluid needs to cool down to obtain an accurate reading.
The fluid level reading on the fluid level indicator will differ depending on operating and ambient temperatures. The correct reading should be within the normal operating temperature range.
Fluid Level Check
Under normal circumstances the fluid level should be checked during normal maintenance. If the transaxle starts to slip, shifts slowly, or shows signs of fluid leaking, the fluid level should be checked.
Scheme 424
- With the transaxle in (P) PARK, the engine at idle, foot pressed on the brake, move the selector lever through each gear and allow engagement of each gear. Place the selector lever in the PARK position.
- Wipe the fluid level indicator cap and remove the fluid level indicator.
- Wipe the fluid level indicator with a clean cloth.
- Install the fluid level indicator back in the fluid filler tube until it is fully seated, then remove the indicator. The fluid level should be within the normal operating range.
High Fluid Level
A fluid level that is too high may cause the fluid to become aerated due to the churning action of the rotating internal parts. This will cause erratic control pressure, foaming, loss of fluid from the vent tube, and possible transaxle malfunction and/or damage. If an overfill reading is indicated, refer to TRANSMISSION FLUID DRAIN AND REFILL .
Low Fluid Level
A low fluid level could result in poor transaxle engagement, slipping, malfunction and/or damage. This could also indicate a leak in one of the transaxle seals or gaskets.
Adding Fluid
| CAUTION | The use of any other type of transmission fluid than specified could result in transaxle malfunction and/or damage. |
If fluid needs to be added, add fluid in 0.25L (1/2 pint) increments through the filler tube. Do not overfill the fluid. For fluid type, refer to the SPECIFICATION CHART .
Fluid Condition Check
- Check the fluid level.
- Observe the color and the odor. The color under normal circumstances should be dark reddish, not brown or black or have a burnt odor.
- Hold the fluid level indicator over a white facial tissue and allow the fluid to drip onto the facial tissue and examine the stain.
- If evidence of solid material is found, the transmission fluid pan should be removed for further inspection.
- If the stain is a foamy pink color this may indicate coolant in the transaxle. The engine cooling system should also be inspected at this time.
- If fluid contamination or transaxle failure is confirmed by the sediment in the bottom of the fluid pan, the transaxle must be disassembled and completely cleaned. This includes the torque converter, cooler bypass valve, coolers and cooler lines.
- Carry out diagnostic checks and adjustments. For additional information, refer to «DIAGNOSIS BY SYMPTOM»(ref-212110-S21926072282005122300000) .
Transmission Fluid Cooler
| CAUTION | Whenever a transaxle has been disassembled to install new parts or because the main control valve body sticks from foreign material, the main control valve body, transaxle fluid cooler and fluid cooler inlet tube and fluid cooler tube must be cleaned and flushed using a suitable torque converter/fluid cooler cleaner. Under no circumstances should an attempt be made to clean the torque converter by hand agitation with solvent. |
When internal wear or damage has occurred in the transaxle, metal particles, clutch plate material, or band material may have been carried into the torque converter and transaxle fluid cooler. These contaminants are a major cause of recurring transaxle troubles and must be removed from the system before the transaxle is put back into use.
Transmission Fluid Cooler - Backflushing and Cleaning
- Carry out backflushing with a suitable torque converter/fluid cooler cleaner. Test your equipment to make sure that a vigorous fluid flow is present before proceeding. Install a new system filter if flow is weak or contaminated.
- To aid in attaching the cleaner to the transmission steel cooler tube, connect two additional rubber hoses to the transaxle end of the steel transaxle cooler tube as follows: Connect the cleaner tank pressure tube to the steel transaxle cooler return tube. Connect a tank return hose to the steel transmission cooler pressure tube. Place the outlet end of this hose in the fluid tank reservoir.
- Turn on fluid pump and allow the fluid to circulate a minimum of five minutes (cycling switch on and off will help dislodge contaminants in cooler system).
- Switch off the fluid pump and disconnect the fluid pressure hose from the transaxle cooler return tube.
- Use compressed air to blow out the cooler(s) and tubes (blow air into the transaxle cooler return tube) until all fluid is removed.
- Remove the rubber return hose from the remaining steel cooler tube.