* Low or No Transmission Fluid: This is the first and easiest thing to check. Low fluid severely compromises the transmission's ability to engage the forward gears. Check the fluid level (with the engine running and warmed up) and condition (it should be reddish-pink and not burnt smelling).
* Forward Clutch Pack Failure: The forward clutch pack is responsible for engaging the gears that allow the vehicle to move forward. If this pack is worn, burned, or otherwise damaged, it won't engage properly.
* Transmission Valve Body Problems: The valve body controls the flow of fluid to the different clutch packs and bands within the transmission. A faulty valve body can prevent the forward clutches from engaging. This is often a more complex and expensive repair.
* Low/Stuck Shift Linkage: While less likely, a problem with the linkage that connects the shifter to the transmission could prevent the forward gears from being selected.
* Torque Converter Issues: Though less common as the primary cause for only reverse working, a faulty torque converter could contribute to the issue. The torque converter is responsible for transferring power from the engine to the transmission.
* Broken or Worn Internal Parts: There might be other internal components within the transmission itself that have failed, such as planetary gears or other clutch packs. This often requires a complete transmission rebuild or replacement.
It's crucial to have a qualified mechanic diagnose the problem. Attempting to diagnose and fix transmission issues yourself can be difficult and potentially dangerous. A mechanic will be able to properly assess the transmission fluid, check for any error codes, and determine the exact cause of the malfunction. They'll have the tools and expertise to properly diagnose and repair the issue, rather than guessing based on general possibilities.
