* Low or No Forward Clutch Pressure: This is the most common cause. The forward clutch pack needs hydraulic pressure to engage and allow forward motion. The problem could be:
* Low transmission fluid: Check the fluid level and condition. Low fluid is a major problem and can lead to significant damage.
* Faulty pump: The transmission pump might not be generating enough pressure.
* Clogged filter or passages: Debris in the filter or internal passages can restrict fluid flow.
* Worn or damaged valve body: A faulty valve in the valve body could be preventing pressure from reaching the forward clutch.
* Leaking seals or gaskets: Internal leaks can rob the system of pressure.
* Forward Clutch Pack Problems: The clutch pack itself might be the issue:
* Worn clutch plates: The friction plates might be worn thin and unable to grip properly.
* Broken or jammed clutch plates: Damaged plates can prevent engagement.
* Stuck or broken piston: The piston that pushes the clutch pack together might be malfunctioning.
* Band Issues (Less Likely): While less likely to solely cause a forward-only failure, a severely worn or broken low/reverse band could *contribute* to the problem by affecting the balance of internal pressures, although reverse usually works well in that case as well. It's still possible a problem with the low/reverse band interferes with forward motion.
Troubleshooting Steps:
1. Check the transmission fluid: Level, color, and smell are crucial. Burnt smelling fluid indicates significant internal damage.
2. Check for external leaks: Look for fluid leaks around the transmission.
3. Have a professional diagnose the problem: This is the most reliable way to pinpoint the exact issue. A mechanic can perform pressure tests and inspect the internal components.
It's highly recommended to not continue driving the vehicle with this problem. Further damage can occur if the transmission is operated while the underlying fault remains unaddressed. Towing the vehicle to a mechanic is the safest option.
