Possible reasons for only reverse gear working in a Hyundai Accent automatic transmission:
Mechanical problems:
* Malfunction or wear of reverse clutches
* Clutch slipping due to low level or contamination of transmission fluid
*Damage to transmission input or output shaft
* Wear or damage to reverse gears
Electrical problems:
* Malfunction of the reverse gear control solenoid
* Broken electrical wiring to the transmission control unit
* Malfunction of the transmission control unit
Hydraulic problems:
*Low transmission fluid level
* The hydraulic filter is clogged or dirty
*Hydraulic pump or valve block malfunction
Other problems:
* Faulty gear selector position sensor
* Damage or adjustment of the gear selector cable
Recommended actions:
* Check the level and condition of the transmission fluid. If necessary, add or replace fluid.
* Check wiring and connectors. Make sure all connections are secure and there are no breaks or damage.
* Perform computer diagnostics. It will help identify fault codes and indicate a possible cause.
*Consult a qualified auto mechanic. If you cannot determine the cause of the problem yourself, contact a professional for diagnosis and repair.