Ok, so we got it fixed. He went to the LHS and got some of the aluminum diff cups and new diff gears and its held up to about 12ish tanks so far. Must have been the diff cups. We shouldnt have any more problems at all anymore cause he also got bulletproof diff gears ordered, and already has bulletproof ring and pinions front and rear and the aluminum diff cups. What a PITA thou-gh. Sheesh. Thanks everyone for the help. He also got the 3 speed-there is no sweeter sound than hearing a nitro shift through three gears. My t-maxx still faster though muahahahaha .