I have a 73 8.25 3.21 suregrip rear I am pulling from my car in a few weeks. Nothing wrong with it, I'm upgrading to an 8.75 with steeper gears. Rearend was overhauled by me and has under 10K easy miles. New MP suregrip carrier, all new bearings, seals, wheel cylinders, drums, brakes. 3.21 gears...