No issues with diff cups or stripping of the spur gear. I just kept her adjusted the way she was from the factory. Wuld not have a clue how to fix either with out taking it a part. Maybe i just don't beat my mt2 hard enough, This little truck has been trouble free, except for a bent driveshaft, and the aluminum shock tower on the rear of the truck got bent jumping it. Thats it though. Im drawing big time blanks on the actual name of the part I bent. Have any of you experienced brain farts like this before?? You know what the part is but you just can't think of it. Its a great truck for sure though.