- Transmission fluid level is low. Check the transmission fluid level and add fluid if necessary.
- Torque converter is damaged. The torque converter is a fluid coupling that connects the engine to the transmission. If it is damaged, it can cause the transmission to slip and not engage properly.
- Transmission gears are worn or damaged. Worn or damaged transmission gears can cause the transmission to slip and not engage properly.
- Transmission control module (TCM) is damaged. The TCM is an electronic control unit that controls the operation of the transmission. If it is damaged, it can cause the transmission to shift improperly or not engage properly.
Diagnosis and Repair:
1. Check the transmission fluid level. The transmission fluid level should be between the "Full" and "Add" marks on the transmission fluid dipstick. If the fluid level is low, add fluid until it reaches the correct level.
2. Check the transmission filter and screen. The transmission filter and screen should be cleaned or replaced as needed. A dirty filter or screen can restrict the flow of transmission fluid and cause the transmission to slip.
3. Inspect the torque converter. The torque converter can be inspected by removing the transmission pan. If the torque converter is damaged, it will need to be replaced.
4. Inspect the transmission gears. The transmission gears can be inspected by removing the transmission case. If the gears are worn or damaged, they will need to be replaced.
5. Check the TCM. The TCM can be checked by using a diagnostic scanner. If the TCM is damaged, it will need to be replaced.
Note: If you are not experienced in working on transmissions, it is recommended that you take your vehicle to a qualified mechanic to have it diagnosed and repaired.
