- Low transmission fluid: Check the transmission fluid level and add more if necessary.
- Faulty shift linkage: The shift linkage connects the shifter to the transmission. If it is damaged or disconnected, the transmission will not be able to shift gears.
- Faulty neutral safety switch: The neutral safety switch prevents the car from starting in gear. If it is faulty, the car will not be able to start in gear, even if the transmission is in neutral.
- Faulty transmission control module (TCM): The TCM controls the transmission. If it is faulty, the transmission will not be able to shift gears properly.
- Faulty transmission: If all of the above components are functioning properly, the transmission itself may be faulty. This is a serious problem that will require professional repair.
Diagnosis:
To diagnose the problem, you will need to do some troubleshooting. Here are a few steps you can take:
1. Check the transmission fluid level. The transmission fluid level should be between the "full" and "add" marks on the dipstick. If the fluid level is low, add more fluid and check for leaks.
2. Inspect the shift linkage. The shift linkage should be connected securely to the shifter and the transmission. If the shift linkage is damaged or disconnected, repair or replace it.
3. Check the neutral safety switch. The neutral safety switch is located on the transmission. It should be properly connected and in the correct position. If the neutral safety switch is faulty, replace it.
4. Scan the car's computer for trouble codes. A trouble code may indicate a problem with the TCM or the transmission.
If you are not able to diagnose the problem yourself, you should take your car to a qualified mechanic for diagnosis and repair.
