if its the sh .28 its inside the engine, you have to take the backplate off, it may be the fuel your using, traxxas top fuel is one of the worst oil wise, i use byrons race proven, never messes up the one ways. you have to be careful with the oil content on an internal one way bearing. clean with carb cleaner and take the shaft it goes on and scuff it up with some fine sandpaper. this should take care of the problem for a while.