[racingdwarf]

Yer Looking at the photo of the diff bolt the end threads that go into the nut look a little flat compared to the threds further up the bolt I would replce the diff nut holder and nut etc during rebuild, just to be sure. what sort of noise was the car making?a smooth slipping noise? or a crunchy one?? also have you had a good hard look at the slipper?

Also have you checked the motor, with brushless you can get some funny noises and also varying strange effects with dodgy sensor boards etc