Possible causes of shocks when switching automatic transmission on Hyundai Elantra:
Mechanical problems:
* Wear of clutches in clutch packs
* Torque converter problems
* Malfunction of solenoids
* Automatic transmission fluid leak
* Malfunctions in the automatic transmission control system
Hydraulic problems:
* Lack of fluid pressure in the automatic transmission
* Dirty automatic transmission filter
* Air in the automatic transmission system
* Faulty automatic transmission pump
Electrical problems:
* Faulty sensors (speed sensor, throttle position sensor)
* Damage to the automatic transmission wiring
* Problems with the automatic transmission control unit (TCM)
Software problems:
* Malfunctions in the software of the automatic transmission control unit
Other possible reasons:
* Worn engine/transmission mounts
* Cardan shaft failure
* Problems with lower engine mount
Recommended corrective actions:
*Consult a qualified transmission mechanic for diagnosis and repair.
* Maintain the automatic transmission in a timely manner, including replacing the fluid and filter.
* Avoid sudden acceleration and heavy towing.
* If the shaking only occurs when it is cold, let the automatic transmission warm up before driving.
* Check the level and quality of the automatic transmission fluid.
* Check the condition of the electrical components of the automatic transmission.