Mechanical problems
* Slipping of one or more gears: Worn or damaged friction discs, faulty solenoids.
* Kicks and jerks when switching: Wear of rubber seals, damage to the planetary gear, malfunction of the torque converter.
* Extraneous noises (hum, buzzing, grinding): Bearing wear, gear damage, lack of transmission oil.
* Transmission oil leaks: Worn or damaged oil seals, seals or gaskets.
Electrical faults
* Faulty solenoids: Missing or incorrect control signal, faulty wiring.
* Sensor problems (speed, crankshaft position): Incorrect data transmitted to the electronic control unit (ECU) of the automatic transmission.
* Incorrect operation of the automatic transmission ECU: Errors in the firmware, malfunction of electronic components.
Hydraulic faults
* Insufficient transmission oil pressure: Worn or clogged oil pump, leaking piping system.
* Damage to the valve body: Clogged or damaged valves, faulty pressure regulator.
* Problems with the torque converter: Wear of the lock-up clutch, damage to the blades, insufficient transmission oil volume.
Other faults
* Coolant leaks: Coolant gets into the transmission oil, which leads to its contamination and disruption of the automatic transmission.
* Faulty wiring: Breaks, short circuits or poor connections that prevent the automatic transmission control system from working correctly.
* Contaminated transmission oil: Dust, wear debris and other contaminants can clog the hydraulic system and cause premature wear.