Possible reasons for the automatic transmission kicking when changing gears:
Mechanical problems:
*Hydraulic transformer malfunction
* Worn or damaged friction discs
* Problems with the transmission control module (TCM)
* Malfunction of solenoid valves
*Low transmission fluid level
* Contaminated or old gear oil
Electrical problems:
* Faulty input and output shaft speed sensors
*Faulty throttle position sensor
* Open or short circuit in TCM wiring
Software problems:
* Bugs in TCM software
* Outdated software
Other possible reasons:
* Worn engine and transmission mounts
* Worn or damaged driveshaft
* Incorrect transmission fluid level setting
*Using inappropriate transmission fluid
What to do if the gearbox kicks:
* Check the transmission fluid level and add if necessary.
* Replace the transmission fluid and filter if it hasn’t been changed in a while.
* Diagnose the transmission using a trouble code scanner.
*Consult a qualified mechanic for further diagnosis and repair.