Possible causes of grinding noise after replacing an automatic transmission:
1. Lack of transmission fluid
* Check the fluid level and add if necessary.
2. Worn transmission parts
* Improper installation or worn gears, shafts or synchronizers may cause grinding noise.
3. Incorrect shift cable adjustment
*Adjust the shift cable to ensure proper gear shifting.
4. Problems with the torque converter
* Fluid leakage or contamination of the torque converter may cause a grinding noise.
5. Worn bearing
* A worn bearing in the transmission may produce a grinding noise, especially when shifting into neutral.
6. Faulty bushings
* Worn or damaged bushings may allow vibration resulting in grinding noise.
7. Clutch malfunction
* A slipping or burnt clutch may make a grinding noise.
8. Problems with the differential
*Damaged or worn differential parts may produce a grinding noise when turning.
Diagnosis and elimination:
* Check the transmission fluid level and add fluid if necessary.
* Take the vehicle to a mechanic for diagnosis.
* He will check the condition of the transmission, including gears, shafts, synchronizers, bushings, bearings and differential.
* The transmission control system, including the shift cable, torque converter and clutch, will also be checked.
* Depending on the diagnosis, the necessary repairs or replacements will be made.