I just pulled the cover off of the rearend in my '76 Century. It has the 8.5" Buick rear with bolt-in axles, 2.73 non-posi. I have a 8.5" 10 bolt posi and 3.23 gears from a '77 Trans Am and I believe it had C-clips. Will this setup fit my housing? Would either the gears or posi fit? I'd like to get some improvement out of this, either posi or better gears preferably both. What is the spline count of the Buick axles? I figured why pull them if I can't use the parts I have. Mike
Mike, Hello. Both rears use the 28 spline 8.5 axles, 30 spline 8.5 axles did not come out till '88 production. The #8 c-clip posi carrier will work in a stock axled 28 spline bolt-in axle rear, though the carrier will prob need rebuilding (new clutchs-shimmed up) for optimum posi capability. Used 3.23's can be set-up, but often will take much much more time than new gears. Being used GM 8.5's, might start with an .038 or .039 pinion shim, then after reassembly, setting B/L at .008-.010 & applying pinion drag, carefully study the patterns. If pinion was rel loose in the T/A rear, chances are, the backlash was really out there (sloppy), & the ring & pinion will have abnormal wear, & you will be in for some noise. Such reassembled loose pinion used gears often don't respond well to B/L being "sucked back in" to .007-.008, at least at stock pinion depth. Sometimes, in such a case, one can get by by going to .001 thicker pinion shim, then setting B/L to .010 to .012. Did you tear down the T/A rear, or were the parts separate when you received them? :3gears: Roger
Thanks for the info Roger. I'm sort of relieved that I will be able to try this stuff out after stashing it in my basement for so many years. The setup came out of a friends TA nearly twenty-five years ago so it is a relatively low mileage unit. I may or may not have helped pull them but I can say they were probably running quiet because all he wanted to do was move up to a 3.73 r&p and posi from a Z-28. The pinion still has the factory bearing in place so I have somewhere to start for setting it up. I thought I would try shimming the clutch pack up a bit to help it out. Anything has to be better than the open rear. If it is still too loose I'll pick up a fresh clutch pack. I can put up with a little bit of noise from the rear but not too much because the car cruises quietly even with the 455 I installed. Mike
