Having a noisy issue on both wheels and will have to prevent damages. I have a 1967 Bonneville Superior ambulance, the differential is 10 bolts. I found one used and rebuilt 3 hours south and the seller is pretty unclear on measurements. He said the differential is from a 1966 GTO and told me "59 inches hub to hub". Since it's hard to get a 6 hour drive for correct measurements I want to know if a 1966 10 bolts differential from a GTO is compatible with a 1967 10 bolts Bonneville.
Called the seller since he was unclear about how to measure, his 59 inches center wheel/center wheel I have 64 on my ambulance so I think this noisy bearing problem sounds like a rebuilt... ouch
I would say it probably needs new rear wheel bearings by your description that both rear wheels are noisy. The bearings should be a pressed fit on the axle and probably not that expensive. It would certainly be a lot easier to replace the wheel bearings than the entire rear axle assembly.
I have two rear diff's for my Beaumont. One 12 and the other is a 10 bolt.
The measurement to determine width is taken from inside of brake flange on the axle tube to the inside on the opposite side and they are the same width for both 10 and 12 Bolts.
That measurement is 54 " , I just measured the 10 bolt to be sure.
What makes the difference with these particular years especially in the A body cars is the location of the upper bushing mounts on the differentials. The are 1/2" further back as compared to the 68 and newer ones.
Good luck
Dale
-- Edited by silver steak on Sunday 18th of June 2023 07:57:18 AM
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New Brunswick , 1950 Pontiac Silver Streak 2 Dr Sedan, 1967 Beaumont, 1985 Sierra 1500 One Owner
If you are buying a used diff, it may not be much better than what you have. Youll go through a lot of pain and expense to find out? May be much better off pulling your axles and bearings and replacing what needs replacing.
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63 Parisienne sport coupe (The Big GTO), black, maroon interior, 409 4 speed; former owner of a 59 El Camino, 63 Corvette SWC, 62 Chev Bel Air SC. 1963- Pontiac top selling car in Canada
Mahone Bay, NS Still not old enough to need an automatic
Check rockauto for parts bonneville vs GTO? To see whats the same for bearings and axles?
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63 Parisienne sport coupe (The Big GTO), black, maroon interior, 409 4 speed; former owner of a 59 El Camino, 63 Corvette SWC, 62 Chev Bel Air SC. 1963- Pontiac top selling car in Canada
Mahone Bay, NS Still not old enough to need an automatic
If the diff for your 67 Bonneville is anything like a 70 Bonneville, it's completely different than one from a GTO. While the cover might have 10 bolts on the cover, the B-Body (Bonneville, Catalina) diff is physically much larger than the A-body (LeMans, Tempest, GTO) diff. And I'm not just talking brake drum to brake drum measurement.
You have an Eaton 8 7/8 rear end. 65 to 70 full size American Pontiac. Bearings and seals are available. I can get you numbers if you need them. I have spare axles from a 66 Bonneville and a 65 Catalina if your axles are damaged. These diffs are not the same as Chevrolet and not the same as A body GTOs
