Big Rock BIG ROCK DIFF UPGRADE PROBLEM

[arrma 43]

I have the arrma big rock. I recently upgraded the rear diff gears to metal but when I reassemble, the gears mesh is to tight when tightening yoke diff case , why is this?? Never had this problem with the composite gears in there? Same with internal sun gears housing, to tight?? i BOUGHT THE METTAL CORWN, AND IMPUT GEAR IF NEW CASE, EVEN THE INTERNAL GEARS WONT MOVE WHEN TIGHENING CASE? CANT USE MY TRUCK NOW,

just bought hobbywing quic run version 2, 150 amp esc for truck. I set my radio up used the program card, and when running truck forward it starts off glitching in my drive shaft of my car, same for reverse then runs normal. This happens all the time, not to smooth?? Whats wrong here??