A strong shock when engaging the reverse gear of an automatic transmission can be caused by the following reasons:
1. Low transmission fluid level:
* Check the transmission fluid level and add it to the recommended level if necessary.
2. Slipping of the reverse clutch pack:
* The reverse clutch pack may be worn or dirty, causing it to slip and bounce when engaged.
3. Worn or damaged components:
* Worn or damaged sun gears, planetary gears, or other automatic transmission components may cause shock when shifting gears.
4. Solenoid malfunction:
*A faulty reverse shift solenoid may prevent proper shifting.
5. Electrical problems:
*A poor connection or faulty wiring can cause shifting problems.
6. Hydraulic system problem:
*Low hydraulic system pressure or leaks may affect gear shifting.
7. Software glitches:
*In some cases, problems with the transmission control module software may cause shock when shifting gears.
It is recommended that you contact a qualified mechanic to diagnose and correct the problem. They will perform inspections, diagnoses, and repairs to resolve the problem and restore smooth shifting.