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Pontiac differential?

Old 02-16-2017, 11:39 AM
J+M is offline
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Default Pontiac differential?

I'm working on my differential in my 1968 Chevelle, (pinion seal leak, axle seal leak) and I'm having the most difficult time trying to identify it! It's still in the car so that's half my battle but I've sanded down paint in all the typical gm code locations. I finally found some coding under the brake line drivers side rear tube. I'm starting to think is a Pontiac Diff? It has bolt in axles. Some sort of limited slip? Don't see any clutch pack in center or the gov type posi. It has a large N on top near the pinion. Its a 10 bolt. I believe 8.2"? On the main casting it has CFD on drivers side and 9795084 on passenger side with 222 above that. The coding I found on the axle tube (i believe because it is very lightly stamped) is 247 247 7H. Again, that's just what I'm making it out to be. From the research I've done there should be a 2 letter code stating the gear ratio. (which is 3.55 by counting teeth as well as looking at the coding on the ring gear stating 39-11 1968). I guess what I'm trying to figure out is what is this thing out of?? Is this even a rebuild-able carrier? Thanks! I'm attempting to post pictures with no luck so I'll have to try and describe it: it has 4 spiders on a cross shaft with 2 side gears. The opening to see into the carrier is much smaller than a normal GM carrier. I don't think one of the spiders could even come out of this opening. As far as the diff housing goes it looks like a typical 8.2" housing with the 4 little nubs at 5 and 7 o'clock positions. Thanks again!
Old 02-27-2017, 04:14 PM
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My guess is that axle was originally fitted to a Pontiac Tempest/LeMans/GTO. 2 character code would be YH for that ratio. The original car would likely have been an automatic transmission without A/C.

The N on the housing is nodular iron casting which is the desirable HD axle that was available via special order (standard for Ram Air I, II & IV)

Definitely not a standard Pontiac axle......Pretty strong, especially if the original axle shafts are present still....Some say as strong as the 12 bolt axles that came out in early 70s.
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