Rear Diff Ring/Pinion Binding

[tacky187]

So I am working on rebuilding a rear end for a friend's 5ive T 1.0. It was in bad shape and had been left out in the weather for awhile. I have the diff rebuild and cleaned some rust off the bearing inserts. I have brand new bearings in the case and the diff pinion has the default shim on it. When I put the diff in place with the inserts, the diff ring and pinion spin great. But when I put other side of the case on and tighten it down, the ring and pinion spin really rough; kind of "chunky".

Any thoughts on why it's binding? Or how I can fix it?

 

[Rep732]

Yep I've been there myself, make sure the pinion bearings are bottomed out in the case, the issue is the pinion is sitting too deep into the case and causing the crunchy lash your describing. Remove the shim and see if it gets better, also when the diff is together push the diff away from the pinion gear, the bearings may not have found there spot yet on the diff cup.