When I started the engine I hear a ringing noise and after I stopped the engine I can't move the truck back and forth. The gears were meshed well before the engine started. This happened twice. The first time I used one piece of paper the mesh the gears and the second time two. The engine is secured and there is no loose screws. What is causing the gears to be not correctly meshed when the engine starts and how do I fix this?

gonna assume this is a nitro and its between the clutch bell and spur gear.


are the berrings in good shape? if so is the ring gear after market? if so it may be out of round.

im not sure what vehicle you are working on so its hard to say what the problem is exactly.

Make sure you locktite the screws and let them dry over night.
check the bearings