My nitro car runs fine but will not move. Whats wrong?
If the engine will run correctly, but the car won’t move, the most likely problem is that something has come loose in the drivetrain. Start at the rear wheels and make sure the nuts that hold them onto the axles are tight. If they are loose, the axle will turn inside the wheels. Now move inward along the driveshafts to the differential case. If there are universal joints at the differential case, they are retained with small set screws. They hold the drive joint onto the small stub shafts that come out of the case. If they have come loose a bit, the stub shaft will rotate, but the drive joint won’t. Align the drive joint so that the set screw will tighten onto the flat portion of the shaft. This may require some disassembly of the suspension to get access. Finally, check the main gear, and make sure that it’s tight on its shaft. If a slipper clutch is a bit loose, the main gear will turn, but power won’t be transferred to the gearbox. You can easily see this when the engine’s running.
