Transmission has failed whilst in 4wd. have checked fluid level all ok, when gear is engaged vehicle lurches slightly but wont drive forward or reverse. When we checked the fluid level the pan was overflowing.

If your 1994 Toyota Camry is only moving in reverse and not forward, there are a few potential causes for this issue:

1. Transmission Issues: One possibility is that there is a problem with the transmission. It could be a mechanical issue, such as a worn-out gear or a failed transmission component, preventing the forward gears from engaging properly. In this case, it would be necessary to have the transmission inspected and repaired by a qualified mechanic.
2. Shift Linkage: Another possible cause could be a problem with the shift linkage. The shift linkage is responsible for connecting the gear shifter to the transmission and selecting the desired gear. If the linkage is damaged, misaligned, or disconnected, it may prevent the transmission from engaging the forward gears. Inspecting and adjusting the shift linkage may be necessary.
3. Transmission Fluid: Low or dirty transmission fluid can also cause transmission-related issues. If the fluid level is low, it can prevent the transmission from properly engaging the forward gears. Similarly, if the fluid is old or contaminated, it may not provide sufficient hydraulic pressure for the transmission to function correctly. Checking the transmission fluid level and condition is recommended, and if necessary, topping up or replacing the fluid.
4. Torque Converter: The torque converter is a component that allows the engine to smoothly transfer power to the transmission. If the torque converter is malfunctioning, it can cause issues with gear engagement and prevent the vehicle from moving forward. A faulty torque converter may require repair or replacement.

It is important to note that diagnosing and repairing transmission issues can be complex and requires specialized knowledge and tools. It is recommended to have your vehicle inspected by a professional mechanic who can properly diagnose the problem and recommend the appropriate repairs.

If you feel the truck lurch forward in drive and backwards in reverse, I would suspect stuck brakes or the parking brake is stuck on due to a bad cable or something. If it doesn't lurch, try giving it some gas and see if it feels like it wants to go back or forward. If no movement at all, i would check the transmission fluid (Remember that you check this while the engine is idling). If the fluid level is in the cold range, i would suspect a failed transmission pump or a failed torque converter. If this is 4x4- check to make sure that the transfer case is in 2hi and not in neutral.

Most likely the fluid level is low. You need to check the fluid level with the vehicle running on most models and add as neccessary

check iff its an adjusteble chifter.if not you have to replace the cabble,
check also transmission fluid level is correct.

First check the selector rod or cable to be sure it selects the right gear.
Check fluid level as well. The planetery gears may be shot!

If your fluid level is right you may have a bad transmission. you need to talk to a mechanic.

I would very first recommend checking your transmission fluid. It may be low and would cause the lurches and the rough shifts.

Check the fluid level for the transmission. If ok, seek help at your favorite transmission servicer.

If engine sounds okay, (when you accelerate, it revs up, etc.) then could be a transmission problem. (assume this is an automatic?)

Check fluid level first, if okay, next suggestion would be to change fluid & filter.

When you select a gear, do you get anything, any slight jolt to the vehicle?

If nothing at all, also might check the transmission lever linkage.

Is this 4WD or 2WD? If 4WD, also need to check transfer case setting, make sure it is properly set.

THE TRANSMISSION HAS FAILED, YOU EITHER HAVE A LOSS OF HYDRAULIC PRESSURE OR AS FAILED FORWARD/DIRECT CLUTCH PACK