Thread: Has anyone upgraded a gm 7.5 and lived to tell about?

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The 7.5 rear in my 86 cutlass has 215k on it. Trying to decide on upgrading the 2.14 open rear to 3.23-3.73 posi, or buying a 9" housing and axles, looking for a used center section. Engine only has about 250 hp, the 9" route is overkill for now. Been checking online for complete rear assemblies, unfortunately they are out of my price range. Been reading about the usual upgrade tricks like welded the tubes, solid crush sleeve and so on. Just wondering of if anyone else is running the 7.5 with any luck. Thanks in advance!

not the best rear end gm put under a car or small truck .welding tubes is something thats been done for many years on 3 part housings . by the time you buy better axles play around with it with better parts it still not going to be the best rear end . i did some ford 9 s were i cut them down and had the axles re drilled to 4 3/4 re splined the axels the stock ford truck axles are very heavy and are the best to re drill the bolt pattern as they have no holes that are needed to be filled for the re drill to chevy and you get the big ford brakes

Wouldn't put money into a 7.5 diff, Okay if you already have one and get a used right hand axle to put on the left side and narrow yourself. Only use for a cruiser, any performance you'll probably break it.

It is a lot better to go to the local pick and pull, find a Ford Explorer 8.8 rear diff. these diffs are quite affordable and almost as strong as a 12 bolt. The newest ones have rear disc brakes.

PS - Do a search on the web for Explorer 8.8 diff. You'll find plenty of info on them.

Thanks for the info, i will look into the 8.8 explored rears. Friend at work is a "ford guy" if I remember correctly he may have said they have 3.73 posi and 31 spline axle's? Need to have one side shortened and adjustable arms, but should still be ahead of the game, seeing parts and labor on a rebuild is easily $900-$1200. Thanks again!

Try this link.

http://rpmcanada.ca/performance/inde...into-a-g-body/

Hope it helps.

Thanks for the link! Going to book mark and check it out after work. Thanks again for everyone's help. Thought I have seen all the build threads on g body rears!

Located explorer 8.8 rear end with posi & 3.73 for $100. Been looking up install swaps online, but can't seem to get a clear picture on what needs to be done. Some say u can't weld the control arm brackets to the top of diff and the housing needs to be cut and centered. Does anyone offer a bolt in housing so I can hopefully just switch all the internals and just bolt it in. And the parking brake pdoblem since this is a disc rear.

If I were going thru the trouble of having to cut the housing /reweld it and have the axle shortened and resplined I'd go with the ford 9" They realy arent that hard to do a good machine shop can do it I built a jig loog ago and do my own now. Axles I send mine to Moser Engineering. in IN. Just my .02

cut the tube to use another passanger side ( short ) axle shaft. this will make the center pinion only 1/2" off. Any passanger side Explorer axle shaft 1995-2001 will work.. Explorer and Ranger guys do it all the time to clear wider tires.. IIRC 2 15/16" is what needs to be shortened out.. The pumpkin on the 8.8 is cast and can't be welded. so you would need to put the brackets on the axle tubes.. Expo- G body swap has been done. Mustang is a closer fit stock but more $$...

At the U pull it I go to, used rear axles are $50. but $100 is a really good price if it's removed.. I managed to get an S10 ZR2 ( same axle over setup ) out w/o dropping the springs. but it took a lot of fighting and a few hrs. not somthing I would do every day

Originally Posted by RUSSW

Located explorer 8.8 rear end with posi & 3.73 for $100. Been looking up install swaps online, but can't seem to get a clear picture on what needs to be done. Some say u can't weld the control arm brackets to the top of diff and the housing needs to be cut and centered. Does anyone offer a bolt in housing so I can hopefully just switch all the internals and just bolt it in. And the parking brake problem since this is a disc rear.

You could try Strange Engineering or Mark Williams but a housing will cost $$$ you.
Russ like Matt says you can get brackets made to weld on the tubes instead of the housing and use the right side axle on the left to shorten the tube. (if it is needed, the Explorer tread width is a bit smaller than the Cutlass?) The emergency brake cables need to be adapted to your cables by making some connectors. This is not a bolt in by any means, you'll need a bit of fabricating experience but is not that difficult to learn if you can find someone to help who has done this sort of thing before. Try a local hot rod or 4 wheeler club, these guys live to do this type of swap.

Thanks again for everyone's input. I think I have found a company that sells 8.8 housing and axle package's for g body cars, stock 7.5 brake components can be used, only things needed would be upper control brackets( they sell separately ) and either a different u joint or yolk,or maybe both. I e mailed them, no response yet. Guess I will have to do it the old fashion way and call them. Thanks again for the help. I kinda feel like I am wasting peoples time with this since I am still short on funds. Just tryin to get my ducks in a row, before I buy the explorer rear end.

Sorry I just realized where i posted this! Wrong forum d@&n it! Can anyone give me advice on dealing with insurance claim adjuster? My car was backed into in my apartment parking lot, and apparently it does not take much damage for them to total a car! Do I have to take their first offer? Or am I stuck with the It? I will be more than happy to give details of vehicle and damage if it's needed. Any help in this matter will greatly appreciated!
Thanks, Russ.