Possible reasons:
Transmission problems:
* Worn or damaged friction discs
* Faulty gear shift solenoids
* Problems with the hydraulic control unit
Engine problems:
* Faulty spark plugs or ignition coils
* Clogged fuel injectors
*Low compression in cylinders
Electronics problems:
* Errors in the operation of the electronic control unit (ECU)
* Faulty sensors (such as camshaft position sensor or speed sensor)
*Wiring problems
Other possible reasons:
*Low transmission fluid level
* Contaminated transmission fluid
* Worn transmission oil filter
* Damage to the driveshaft
* Problems with engine or transmission mounts
Diagnosis and elimination:
1. Check the level and condition of the transmission fluid. The fluid should be at the appropriate level and should not be dark or burnt.
2. Perform diagnostics using an OBD II scanner. It can identify trouble codes that indicate a specific problem.
3. Conduct a visual inspection of all transmission components. Pay attention to wear, damage or leaks.
4. Contact an experienced mechanic. Accurate diagnosis and repair may require specialized equipment and knowledge.
Preventive measures:
*Change the transmission fluid and filter regularly according to the manufacturer’s recommendations.
*Use the transmission fluid recommended for your vehicle.
* Avoid sudden gear changes.
* Perform transmission maintenance as scheduled.