Mechanical reasons:
* Wear of clutches or steel discs
* Clogging of the valve body or automatic transmission with metal shavings
* Low transmission fluid (ATF) level or contamination
* Wear or damage to the automatic transmission pump
* Planetary gear malfunction
Hydraulic reasons:
* Low fluid pressure in the system
* Torque converter malfunction
* Clogged or damaged valves and channels in the valve body
* Malfunction of electronic solenoids
Electrical reasons:
* Malfunction of input/output shaft speed sensors
* Malfunction of the electronic control unit (ECU) of the automatic transmission
* Problems with electrical wiring (breaks, short circuits)
Other reasons:
* Incorrect adjustment of the automatic transmission control cable
*Powertrain Control Module (PCM) malfunction
* Engine problems (insufficient power)