Possible reasons for automatic transmission kicking on a Subaru Forester SF5:
1. Low fluid level in the automatic transmission
* Check the fluid level in the automatic transmission and, if necessary, add the recommended fluid.
2. Contaminated automatic transmission fluid
* Change the automatic transmission fluid regularly (usually every 30,000-60,000 km) and install a new filter.
3. Faulty automatic transmission solenoid
* Solenoids regulate the flow of fluid in the automatic transmission, and their malfunction can lead to incorrect shifts.
4. Faulty input/output shaft speed sensor
* These sensors transmit information about the speed of rotation of the shafts to the automatic transmission control unit, which is necessary for correct gear shifts.
5. Faulty automatic transmission control unit (TCU)
* The TCU electronically controls the operation of the automatic transmission and its malfunction can lead to various problems, including kicking.
6. Wear of automatic transmission parts
* For example, worn clutches, steel discs or bearings can cause slipping and kicking when shifting.
7. Transmission malfunction
* Problems with the differential, drive shafts or gearbox can transmit vibrations to the automatic transmission, resulting in kicking.
8. Incorrect shift cable adjustment
* Incorrect shift cable adjustment can limit selector travel range and cause shift kick.
9. Torque converter slipping
* The torque converter transfers power from the engine to the automatic transmission, and slippage can result in rougher gear changes.
10. Too aggressive or conservative shift mode
* Some automatic transmissions have the ability to adjust the shift mode, and too aggressive or too conservative a mode can cause kicking.
Diagnostics:
* Connect the diagnostic scan tool to the vehicle and check for automatic transmission related fault codes.
* Check the level and condition of the fluid in the automatic transmission.
* Consider performing a torque converter slip test.
* Check the functionality of solenoids, sensors and other automatic transmission components using special tools or a diagnostic scanner.