I am trying to figure out what rear end is in my car so I can order some 3.73 gears for it. It seems to be a 8.75 with a posi unit and 2.73 gears. It has a 10 bolt cover and has 12 ring gear bolts. 3 inch axle tubes and c clip axles. The only axle tube numbers I can see are 2tw. I have not pulled an axle out to check spline count. Are there any 3.73 gear sets avaliable for this series carrier or can I use a ring gear spacer? Is it even worth the time? If this is a 8.75 rear end what the heck is it doing in a 82 caprice classic? Maybe im better off selling it to someone else for there project due to its lack of aftermarket support. Any help would be appreciated.
I'ts the early 1970's oddball 10/12-bolt hybrid. I believe called a Type "O". There is zero aftermarket support for this rear...nothing beyond bearings and seals.
Unless it is the correct length, has correct brackets to fit your application and a gear ratio you want in it already you would be better to sell it off...if you use it and break it you'll lose that possibility.
Thanks for the reply ericnova. That wiki site is very helpful and is where I found pretty much all off my info on this rear end.
Whats weird is this rear end is what came in my car when I bought it a few years ago. Someone must of swapped it in a while back. 2.73 with a posi would probably be good for something with a 4 speed and a decent power plant but in my caprice with an overdrive tranny not so much.
The 8.5 10 bolt was available for your car. Many of them had the 7.5, but police cars and some others got the 8.5. I'm not sure, but the '94 to '96 Impala SS rear end might fit. The 8.5 would be a much better rear end for you to invest some time and money into.
The Type O (as in Oldsmobile) has a 12 bolt cover and a 10 bolt, 8.5" ring gear and was only used in 1966-1970 Cutlass/442 cars. This axle clearly isn't one of those. Some of the full size cars did get a 10 bolt cover, 12 bolt ring gear axle. Try DTS for parts.
Tried dts for a ring and pinion but no luck. I would put a impala ss rear in my car but I dont want to deal with the different wheel bolt pattern or the disc brakes and not to mention they are rare in my area and the only one I could find was very expensive. I do have a 7.625 rear from a 90 caprice (I think its a 7.625 anyways). It also has 2.73 gears but I am thinking of going 4.10s now. That would give me 2400 rpm at 70... not bad I guess. An engine swap with 300-350 horse is in the future. You guys think a 7.625 with a eaton posi or a powertrax with hold up ok with that kind of power to it? Once again thanks to you guys that have replied, your advice is very helpful.
The 7.5" should be okay at that power level, over 400 hp would lead to problems with a heavy car and good traction.
I thought the 90 Caprice would be an 8.5"?? or is that only the higher hp models like Police and the SS Impala with the 5.7 engine. I know the 5.7 wagons (Buick Roadmaster and Chevy Caprice) have the 8.5"
If you are going to invest money in a rear end the start with a good rear end. The 7.5 is always questionable with a V8, and if it breaks then you have lost your investment. Just look around for a 8.5 and put your money in it. You can find 8.5 rear ends for your car.
I think the 7.5 was standard in everything but the wagons and impala ss. Also the wagon rears wont fit in the sedans.
I found one 8.5 near me but the dude wants $700 for it. Its a posi and has 3.73 in it. Mite go for it since I would be in it for less than a set of gears and a posi unit for a 7.5.
You should be all over that, before it gets away....., you'd have that much cost into the gears and differential for either a non-posi 8.5" or the weak 7.5". ....and it will be a afternoon bolt-in, no gear set-up required
If I could find a police version caprice/implala in a junkyard I would grab an axle out of it in a hartbeat but I have never found one. Even just a regular old caprice is near impossible to find around hear... most of them have been crushed long ago.
I have been told the lower control arm mounts are wider than on a sedan axle, not sure of the truth behind it though.
I looked at the ss axle agian and it is missing the rotors, calipers, caliper brackets, and backing plates... not good. But the more I think about it the axle is decently priced except for the missing parts.
You can put drum brakes on the SS rear end. I built a drum brake rear end for a SS and put the SS disc brakes on it. They were a direct swap. I'm not sure, but the 8.5 truck drum brakes might fit. I think the Impala rear end has the larger bolt pattern for the brake backing plate.
That would be cool if the drum brakes bolted on the ss axle. I think the ss has a 5 on 5 wheel bolt pattern and my car has a 5 on 4.75 pattern. Is a machine shop capable of redrilling the axles to a 5 on 4.75 pattern?
Also how can you tell what posi unit is in the ss axle by just looking at it? I guess someone put in some 3.73s and the posi looks aftermarket. I just want to make sure it doesnt have an auburn or an ebay "eaton posi-style" in it.
That would be cool if the drum brakes bolted on the ss axle. I think the ss has a 5 on 5 wheel bolt pattern and my car has a 5 on 4.75 pattern. Is a machine shop capable of redrilling the axles to a 5 on 4.75 pattern?
Also how can you tell what posi unit is in the ss axle by just looking at it? I guess someone put in some 3.73s and the posi looks aftermarket. I just want to make sure it doesnt have an auburn or an ebay "eaton posi-style" in it.
Nothing totally wrong with the Auburn, just can't be rebuilt by the at-home mechanic or local shop.
If it works, use it until it's worn out or you overpower its bias and spin just one tire in certain cases, and then upgrade. At least its not that POS Eaton Gov-Loc.
I had to replace a 8.5 in a '96 Impala SS because the Auburn exploded inside. It busted 3 holes in the cast iron center part of the housing. Had to replace the whole rear end.
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