gee id have to see a picture to tell you for sure what the problem was......was the clutch bell tore up too? if so id say a small rock could have been the culprit


also ive seen some cars that have spur gears that have a slight wobble from the factory..im not sure why this is except mayby it helps with wear of the 2 gears...???????????????

also all gearing mesh whether it be rc cars or any other type of machinery will have a tight spot and a loose spot...this is real noticible on a bicycle chain or a motorcycle chain there will always be a tight spot...you should always set the chain tension or in this case gear mesh while it is at the tight spot......