Mechanical faults:
* Wear of friction clutches
* Damage to gear teeth
* Torque converter failure
* CVT belt or chain slippage
* Low automatic transmission fluid level
* Contaminated automatic transmission fluid
Electrical faults:
* Malfunction of solenoids
* Electrical circuit break
* Failure of sensors
* Malfunction of the automatic transmission control unit
Incorrect operation:
* Towing heavy loads
* Abrupt starts and stops
* Late replacement of automatic transmission fluid
* Automatic transmission overheating
* Driving in low gear at high speed
Other reasons:
* Wear and tear of internal wiring
*Corrosion
* Clogged automatic transmission filter
* Malfunctions of the engine or other related systems