Preliminary Inspection
Preliminary Inspection
Check the following items 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 must also be understood when the concern occurs, 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 system provides information that must be used in both determining the actual cause of customer concerns and carrying out the appropriate procedures.
Use the following procedures when verifying customer concerns for the transmission:
Determine Customer Concern
NOTE: Some transmission conditions can cause engine concerns. The torque converter not disengaging may stall the engine.
Determine customer concerns relative to vehicle use and dependent driving conditions, paying attention to the following items:
- Hot or cold vehicle operating temperature
- Hot or cold ambient temperatures
- Type of terrain
- Vehicle loaded/unloaded
- City/highway driving
- Upshift
- Downshift
- Coasting
- Engagement
- Noise/vibration- check for engine rpm, vehicle speed, shift, gear, range or temperature dependencies
Check Transmission Fluid Level and Condition
Transmission Fluid Level Check
NOTICE: Do not drive the vehicle if the transmission fluid level indicator shows the transmission fluid below the DO NOT DRIVE mark or internal 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: 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 overflow condition when the vehicle reaches normal operating temperature. Transmission fluid level must be checked while in the normal operating range of 66°-77°C (151°-171°F) to make sure that the transmission fluid level is accurately checked and transmission fluid level adjusted correctly.
Check the transmission fluid level 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 until the transmission fluid reaches normal operating temperature.
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.
Blade Design Transmission Fluid Level Indicator Used on Some Applications
Bullet Design Transmission Fluid Level Indicator Used on Some Applications
High Transmission Fluid Level
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
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 Material chart.
Transmission Fluid Condition Check
1. Check the transmission fluid level.
2. 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.
3. If evidence of solid material is found, remove the transmission fluid pan for further inspection.
4. If the stain is a foamy pink color, this may indicate coolant in the transmission. Inspect the engine cooling system at this time.
5. If transmission fluid contamination or transmission failure is confirmed by the sediment in the bottom of the transmission fluid pan, disassemble and thoroughly clean the transmission, including the torque converter, transmission fluid coolers and transmission fluid cooler tubes.
6. Carry out diagnostic checks and adjustments. Refer to Diagnosis By Symptom Diagnosis By Symptom.
Water in Transmission Fluid
To correctly repair an automatic transmission that had water or coolant introduced into the system, completely disassemble, clean and/or replace the following parts:
- All internal and external seals
- All friction material
- Torque converter
- All parts with bonded seals
- All solenoids
- All transmission fluid filters
- Transmission fluid cooler(s)
Prior to installing the transmission, flush and clean the transmission fluid cooler(s), transmission fluid cooler tubes and transmission fluid cooler hoses.