Mechanical faults:
* Wear or breakage of planetary gears
* Wear or breakage of the fluid coupling
* Worn or broken lock-up clutch
* Bend or breakage of turbine or pump shaft
Hydraulic faults:
* Worn or dirty oil pump
* Clogged or damaged oil supply channels
* Damage to oil seals or seals
*Low transmission fluid level
* Slipping or incomplete engagement of clutches
Electrical faults:
* Turbine speed sensor malfunction
* Faulty shift lever position sensor
* Malfunction in the transmission control unit
Other reasons:
*Overheating due to lack of cooling or excessive load
* Entry of metal fragments or other foreign particles
* Natural wear and tear during long-term use
* Improper maintenance or repair
Symptoms of an automatic transmission torque converter malfunction:
*Transmission slippage
* Vibration or jerking when shifting gears
* Difficulty shifting gears
*Transmission overheating
* Extraneous noise or whistling
*Reduced engine power
*Transmission fluid leak