If anyone on here has replaced there OEM POSI Diff for a locker or something else or has one iam willing to buy it and pay for shipping!!

 

"Posi" is GM-speak, we don't appreciate that sort of language on this board. You're looking for a Trac-Lok for a Ford 8.8 31-spline rear. If you don't find a used one, they're readily available through both Jeg's and Summit.