I've got a 73 Centurion with a posi. It's seeping oil around the passenger side axle tube and my mechanic says the housing needs to be replaced. He measured the angle on the shock mounts and the passenger side is 2 degrees off from the drivers side. He thinks the passenger tube spun. These full size rears came with 8.5", 8 7/8" and 9 3/8" internals. I haven't been able to determine what I've got in mine, probably 8.5". I'd like to keep the posi but need to replace the housing. Are the housings universal or specific for the gear size? If I get a housing from the salvage yard that has 9 3/8" internals can I put my 8.5" posi in it? If I have to find a housing with the same size gears my chances of finding the right one in repairable condition drop by 2/3.
'71-76 GM B series coil spring rearend ID (wagons had leaf springs) 10 bolt round rear cover should be 8.5. Need to pull a rear drum, if access holes for bolt-in axles, you have bolt-in axle 28 spline 8.5. B,O axle asm plant. 10 bolt round rear cover & no access holes in axle flange, one has 28 spline 8.5 c-clip rearend. C, G, K, W axle asm plant. Note: The above info in regard to 8.5 rear cover shape only carrys any weight for B series 8.5 rears for this chassis! There were at least 5 different 8.5 GM rear covers used from '71+ & ID'ing A-body rears by their shape is a big mistake. 8 7/8 "MP series" rearend 2 cutout rear cover, 10 bolts holding cover to hsg, 12 bolts holding ring gear to carrier, very similiar to 12 bolt Chevy, but carrier is to long. C-clip 31 spline axles used through '75. '76 & later B series MP r/e's received 28 spline axles. '71+ 9 3/8 "Buick" rearend. Cover is round & has 12 bolts. Bolt-in 31 spline axles. Hope this helps. Can't find a suitable hsg to rebuild, clean bare housings can be shipped OOPS or FedEx. :3gears: Roger
