Possible reasons why the automatic transmission stopped moving backwards:
1. Transmission problems:
* Reverse solenoid malfunction
* Wear or damage to reverse gears or bearings
*Low or contaminated transmission fluid
2. Transmission problems:
* Slipping or wear of reverse clutches
* Torque converter malfunction
3. Electronic problems:
* Faulty gear selector position sensor
*Blown fuses or faulty reverse relay
* Problems with the transmission electronic control unit (ECU)
4. Mechanical problems:
* Sticking or broken gear selector mechanism
* Loose or broken transmission control cable
5. Other possible reasons:
* Malfunction of the ABS/ESP unit (may affect the functioning of the gearbox)
* Low battery (may interfere with electronic transmission control)
* Brake system malfunction (faulty brakes may limit reverse movement)
Diagnostics and repair:
*A CT scan and physical inspection of the transmission and drivetrain are required for an accurate diagnosis.
*Repairs may include replacing faulty components, flushing and replacing transmission fluid, resetting ECU adaptations, or more serious transmission repairs.
Important:
* Do not continue to drive the vehicle if the transmission does not move in reverse. This could lead to further damage and unsafe driving.
* Entrust the repair to a qualified mechanic with experience working with automatic transmissions.