Preliminary Inspection
Preliminary Inspection
The following items must be checked prior to beginning the diagnostic procedure:
Know/Understand the Concern
In order to diagnose a concern correctly, the customer complaint or condition must first be understood. Customer contact may be required in order for the technician to begin to verify the concern. The conditions when the concern occurs must also be understood, for example:
- Hot or cold vehicle temperature
- Hot or cold ambient temperature
- Vehicle driving conditions
After understanding when and how the concern occurs, proceed to Verify the Condition.
Verify the Condition
This provides information that must be used in both determining the actual cause of customer concerns and carrying out the appropriate procedures.
The following procedures must be used when verifying customer concerns for the transmission:
Determine Customer Concern
NOTE: Some transmission conditions can cause engine concerns. An Electronic Pressure Control (EPC) short circuit can cause engine misfiring. The Torque Converter Clutch (TCC) not disengaging will stall the engine.
Determine customer concerns relative to vehicle use and dependent driving conditions, paying attention to the following items:
- Hot or cold engine operating temperature
- Hot or cold ambient temperatures
- Type of terrain
- Vehicle loaded/unloaded
- City/highway driving
- Upshift
- Downshift
- Coasting
- Engagement
- Noise/vibration - check for dependencies, either rpm dependent, vehicle speed dependent, shift dependent, gear dependent, range dependent or temperature dependent
- On vehicles equipped with a Power Take-Off (PTO), the PTO must be turned off. For a description of PTO operation, refer to Transmission Electronic Control System Transmission Electronic Control System
Check Transmission Fluid Level and Condition
Transmission Fluid Level Check
NOTICE: The vehicle should not be driven if the transmission fluid level indicator shows the transmission fluid below the DO NOT DRIVE mark or internal transmission failure could result.
NOTE: 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 transmission fluid needs to cool down to obtain an accurate reading.
NOTE: The transmission fluid may be checked in the cold temperature range if the ambient temperature is between 10°-32°C (50°-90°F). Checking the transmission fluid level using the cold range will indicate that the vehicle has sufficient transmission fluid to be driven. Adding transmission fluid using the cold range may result in an over full condition when the vehicle reaches normal operating temperature. Transmission fluid level must be checked while in the normal operating range of 66°-77°C (150°-170°F).
Under normal circumstances, the transmission fluid level should be checked during normal maintenance. If the transmission starts to slip, shifts slowly or shows signs of leaking, the transmission fluid level should be checked.
1. Drive the vehicle 32 km (20 mi) or until the vehicle reaches normal operating temperatures.
2. Park the vehicle on a level surface and apply the park brake.
3. With the park brake applied and one foot on the brake pedal, start the engine and move the selector lever through all the gear ranges. Allow sufficient time for each gear to engage.
4. Place the selector lever in PARK and leave the engine running.
5. Remove the transmission fluid level indicator and wipe it clean with a lint free cloth.
6. Install the transmission fluid level indicator until it is fully seated into the transmission fluid filler tube.
7. Remove the transmission fluid level indicator and inspect the transmission fluid level. The transmission fluid level should be in the designated area for normal and room temperature.
High Transmission Fluid Level
A transmission fluid level that is too high may cause the transmission fluid to become aerated due to the churning action of the rotating internal parts. This will cause erratic control pressure, foaming, loss of transmission fluid from the vent tube and possible transmission malfunction or damage. If an overfill reading is indicated, refer to Transmission Fluid Drain and Refill Transmission Fluid Drain and Refill.
Low Transmission Fluid Level
A low transmission fluid level could result in poor transmission engagement, slipping, malfunction and/or damage. This could also indicate a leak in one of the transmission seals or gaskets.
Adding Transmission Fluid
NOTICE: The use of any type of transmission fluid other than specified could result in transmission failure.
If transmission fluid needs to be added, add transmission fluid in 0.25L (1/2 pt) increments through the transmission fluid filler tube. Do not overfill the transmission fluid. For transmission fluid type refer to the Transmission Fluid Type specification chart.
Transmission Fluid Condition Check
1. Check the transmission fluid level.
2. Observe the color and the odor. The color under normal circumstances should be dark reddish, not brown or black or have a burnt odor.
3. Hold the transmission fluid level indicator over a white facial tissue and allow the transmission fluid to drop onto the facial tissue and examine the stain.
4. If evidence of solid material is found, the transmission fluid pan should be removed for further inspection.
5. If the stain is a foamy pink color, this may indicate coolant in the transmission. The engine cooling system should also be inspected at this time.
6. If transmission fluid contamination or transmission failure is confirmed by the sediment in the bottom of the transmission fluid pan, the transmission must be disassembled and completely cleaned. This includes the torque converter, coolers, cooler tubes.
7. Carry out diagnostic checks and adjustments. Refer to Diagnosis By Symptom Diagnosis By Symptom.
Water in Transmission Fluid
To correctly repair an automatic transmission or transaxle that has had water or coolant introduced into the system, completely disassemble, clean and replace the following parts:
- All internal and external seals
- All friction material; clutches and bands
- Torque converter
- All parts with bonded seals
- All solenoids
- All transmission fluid filters
Prior to installing the transmission or transaxle, the transmission fluid cooler(s), transmission fluid cooler tubes and transmission fluid cooler hoses need to be flushed and cleaned.