[Fitz]

Motorbooks.com has this manual, which shows in great detail just how to rebuild a 12 bolt diff. And, before someone points out that this only applies to 67 trucks, the diff is common to years before and after 67-72. You will need a 1/2 inch drive torque wrench and a dial indicator with a magnetic base and support arm. When I did my diff the gearset was about 270.00, the Eaton Posi 420.00, full install kit (bearings, shims, crush sleeve & gaskets) 88.00. C clip eliminators 160.00, new Strange axles 440.00 so the total was 1380 with new axles. Or just fork over 3 grand and have someone else do it for you. Your choice.