so iv just done my first complete tear down and clean, as well as differential maintenance. I’m to the point in the re assembly that the motor mount as been put back on the chassis , with The motor and all differentials and shafts attaches. However after tightening everything down the center differential has a lot of wiggle and the bearing doesn’t stay seated correctly to the mount and the spur rubs the chassis. It wasn’t like this before what did I miss? I’ve taken it all off and put it back on three times . Help!