Join Date: Jan 2015
Location: Injun Territory, 'Merica!
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Just looking at your pics, the rearend is an 8.2 Pontiac 10 bolt, not sure where you are coming up with the 8.75 description for that rear. The 8 7/8 MP series rear is another style GM rear (sometimes referred to in chevy service manuals as an 8.75), and there is no version of that style rear that bolts in a '72 or earlier A body. By looking at the shape of the diagonal webbing looking at the center hsg from the rear, along with shape of the rear cover is how I'm ID'ing the rear, and I have half a dozen gray iron versions, along with a few nodular HD Safe-T-Track rears. 8.2 Pontiac rear's were used under all '64-69 Pontiac A body's, and all '70-72 Pontiac A & G bodys except those 70-72's factory equipped with a 455 engine.
On this 8.2 Pontiac rear, you can take a 9/16" socket on an extension and fish it through the access hole in the axle flange. Out on the road, in yards, I usually use a large 1/2 drive flex head socket wrench along with a 3/8" adapter and a 3/8 drive extension to remove the 9/16" headed nuts, then yank each axle out.
If the 8.2 Pontiac 10 bolt rear is out of a '70-72 Pontiac A-body, the axles will have tapered axle bearings with external seals. This style of axle bearing next to never goes bad. My old 4.0 Jeep Cherokee had this exact same axle bearing and seal, and both were in excellent shape at over 280K miles of serious abuse, years and years of heavy loading and towing. The external axle seal is a National 712146, the tapered bearing is an A9. You can slide the axle out and see if there is an external seal jammed up out board of the axle bearing..if so, most likely the axle bearing and seal is fine. Replace if you like, I always do on the bolt-in axle 8.5 A body rears that I build.
On the other hand, if the axle bearing has no external seal, one can shine a flashlight up in the axle tubes a few inches, and one will see an internal seal. The early 8.2 Pontiac A body rear's were used through '69, and they use a sealed axle bearing, the RW507C. this style axle bearing is notorious for seizing and spinning the internal race on the axle and thus chewing up the axle. I've literally pulled multiple hundreds of he early sealed axle bearing axles over the years, an I personally will not build the early gray iron 8.2 rears for performance usage. For high point restorations, it's one thing, will go through them. For strong performance A body's, it's an upgraded 8.5 A-body swap, or an upgraded 12 bolt, have picked up blown parts too many times from 8.2's, they just don't have adequate pinion support.