ok, im rebuilding a gm front 10 bolt, and i was putting in the pinion and differential today. i dont have a high enough torque wrench so i used just the impact gun to get the pinion bolt on. seemed to be tight enough. well here is the problem, when i oput the differential in, and fit it, it spins perfectly, but once i tighten the bolts for the ?????(i forgot what the part is called, it holds the berring caps down and holds in the diff. ya i know imn sutpid ) the dfferential doesnt spin. its not the berrings, because its only when i tighten the side witht he ring gear. it meshes the ring gear and pinion gear too tightly. how can i fix this problem? did i not tighten the pinion bolt enough?