69 skylark diff ??????

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Jasonc5
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69 skylark diff ??????

Post by Jasonc5 »

i have a 69 skylark that is baffling me.

Shattered a few teeth on the gear in the car, pulled the old 1 out, It has a Spacer and and GM gear says 39-11 so its a 3.55. Now i cant find any other part numbers anywhere. I ordered a 3.90 BOP thinking it would go right in and it is Alot thicker and would not use the spacer. From what i have been told you are the Buick Goto guy. Any help would be appreciated.
Jasonc5
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Re: 69 skylark diff ??????

Post by Jasonc5 »

also has a timken bering hm 89449 on the pinion.
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monzaz
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Re: 69 skylark diff ??????

Post by monzaz »

Hey Jason we really need to ID your diff before we go any further as the 68-70 Buick rears are way different...BUT since you say you have a 449 bearing I am hoping someone did a rear swap already.

DOes the rear have bolt in axles?
How many spline pinion for the yoke is the count 25 or 27?

Does your housing center section casting have upper cast webbing diagonal parrelell or non from the upper control arm mounting area to the pinion yoke.

Pictures are always the best. Jim

You can reference the J D Race.com I D DIFFERENTIAL section and see if you can match up a rear that looks like yours too. Remember these are ACTUAL pictures and will be IDENTICAL. Jim

spacer deal. Well if you had a 3.55 gear and needed a spacer then you will certainly need the spacer again with the 3.90. They use the same carrier so NO QUESTION of a doubt on that.
J D Race
Jasonc5
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Re: 69 skylark diff ??????

Post by Jasonc5 »

yea someone swapped a Pontiac rearend in it.

Thanks for your pics as they did help.

whats funny is i had people telling me there all the same, no issues and i do not know what im talking about with the 69 buick rearend.
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monzaz
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Re: 69 skylark diff ??????

Post by monzaz »

Yah, So I guess you know who really rebuilt there rear and who did not...LOL. Jim

1964-1967 Buicks all use the Pontiac ring and pinion set-up which is the most common and well supported by the aftermarket.

1968-1970 were the beefed up 8.2 Buick rears with the 12 bolt driver side carrier bearing and the MUCH larger inner pinion bearing...BIGGER than the 12 bolt chevy even...

1971 1972 were the last of the Muscle car era and the start of the 10 bolt 8.5 corparate rears which still are being produced today. MILLIONS and MILLIONS were made from 1970 -2009 cars trucks SUVs camaros a-bodys B-body impala Buick Olds Pontiac full size, 1/2 ton truck even Grand Nationals used them...

So which one do you have? OR do you have a chevy rear under the car...lol. This is why I ask as it could be many different rears that will fit your 69 a-body car. Jim
J D Race
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