GM 7.5 10 bolt Questions.

[Texas82GP]

I have the factory manual for my 83 GP. I'd be glad to scan the section in on doing the differential work for you. I'm going to have to look for it and read it. Bonnewagon has me intrigued. We also have the factory manual for my brother's 78 Z28 so we should have the proceedure between the two books.

 

[Turbo Zach]

You need to talk to Doug at Quick Performance in Ames! He can get you the parts you want at a cheeper price, answer your questions, and do qout on them doing the work if you want. You should take a road trip some time and see all the hotrod stuff and thing's he offers. They do more than nine inch rearend. Did you see the 8.5 open rearend for sale on Craigslist for 700 bucks?

 

[MrSony]

Forget Chiltons, or even Motor, which is better. Only a factory GM manual will teach you properly. I have been looking for an aftermarket book that explains it but have not found one yet. Every once in a while a car mag will do an article about gear swaps, but then they have a shop do it. (duh). But I think you are a smart kid and I think you can handle the job. I want you to learn the right way so you can be good at this. It is another lost art that needs young guys to keep alive. So spend your time finding the factory manual for your car over the winter. They can be pricey unless you score a deal online or a swap meet but the factory information is invaluable. Epay is good and can be expensive http://www.ebay.com/itm/1985-Buick-...ash=item1e70c86b3a:g:C9cAAOSwDuJWvCSx&vxp=mtr or cheap http://www.ebay.com/itm/1985-BUICK-...ash=item1c75464506:g:NbEAAOSwPcVV2mRj&vxp=mtr depending on quality. Check out sites like this one- http://www.factoryrepairmanuals.com/

Cool man, thanks.

 

[MrSony]

You need to talk to Doug at Quick Performance in Ames! He can get you the parts you want at a cheeper price, answer your questions, and do qout on them doing the work if you want. You should take a road trip some time and see all the hotrod stuff and thing's he offers. They do more than nine inch rearend. Did you see the 8.5 open rearend for sale on Craigslist for 700 bucks?

No, I didn't. I did a search for about 10 minutes using different words and phrases, you know how CL super picky about what you type and how you word it, and found nada. Maybe the post expired. If it pops back up in spring I'll consider it but the most economical thing for me right now (spring time) is to just beef up mine. Thanks for the tip though.

 

[Bonnewagon]

Jared and Mr Sony- don't be put off by the technical jargon in the factory manual. I scratched my head for many hours trying to understand the concept behind the relationship of the ring and pinion gears. The gear sets are matched at the factory to mesh perfectly and must never be separated or mixed with others. This is where the pinion depth, backlash, and tooth contact pattern come in. Really sharp guys can set up gears just by looking at the tooth contact pattern because that is the ultimate indicator of the gear's relationship to each other. I am not one of them! Not only do the gears have to mesh properly but they must be held tightly in suspension in the housing. That is the purpose of the bearing pre-load- so they don't move out of position. Otherwise the torque of the motor would twist them out of alignment and then they would get noisy, wear out, or even break. Some slick race car techs set up gears anticipating the super high loads placed upon the gears and add some "windage" to the settings. That is fine for a set that only has to last one race. But the factory method sets up gears so they will run smooth and quiet for the life of the car. Finally, be prepared to fail. My first attempt lasted about 15 feet before the ring gear lost 6 teeth. Ouch. My own fault- I disregarded the manual- and paid the price. So practice on a gear set you can afford to lose, not your dream set. I will help all I can, just ask.

 

[Opie Knievel]

I have a factory manual for the '86 Monte Carlo, El Camino and Caprice as a PDF. It's pretty handy. I have a full service manual on my phone. After Bonnewagon mentioned how good it described the rear end, I gave that section a skim and wow, it had a lot of info. I definitely agree, I haven't seen it covered that good in any other manual.

PM me and I'll send you a copy of the PDF. That goes for anybody who'd like a copy.

 

[64nailhead]

I would suggest turning the original pinion bearings into setup bearings by increasing the inside diameter so they will slip on and off until you figure out the pinion shims.

Setup bearing is definitely needed, but you need to, or should use a new bearing of the same brand. Using a worn used bearing is is goign to be off by at last .001-003".

Mr. Sony,
Bonnewagon is 110% correct about finding a manual (sounds like someone here will send you a copy). And that advice applies to most everything mechanical iif you don't know how to do something - basically, it eliminates the guessing - most of the time. Making this repair is really a pretty simple ordeal. But as mentioned by Texas82GP, it takes patience. To get the correct wear pattern you might have to pull the pinion in and out upto 5 times and carrier more than that. But other times things will fall right into place and you'll get it on the 1st or 2nd install.

Tools other than those mentioned already - 3/8" or 1/2" torque wrench, and some form of in/lb rotational torque wrench

I like the Quicks kit - good price, but add a set of Moser axles. Quicks gets them as cheap as anyone and they usually have some form of free frt deal around the holidays. And if you can find a local shop that press the bearings on for you, then that would be great. I do it several times a year for locals - takes 10 minutes.

Edit - have you considered grabbing one of these : http://rover.ebay.com/rover/1/711-5...0001&campid=5335822911&icep_item=162283925360 We used in a 400 WHP application for a full summer - they are bulletproof IMO. We bought ours for $125.

 

[Opie Knievel]

I have a factory manual for the '86 Monte Carlo, El Camino and Caprice as a PDF. It's pretty handy. I have a full service manual on my phone. After Bonnewagon mentioned how good it described the rear end, I gave that section a skim and wow, it had a lot of info. I definitely agree, I haven't seen it covered that good in any other manual.

PM me and I'll send you a copy of the PDF. That goes for anybody who'd like a copy.

Instead of making people message me and wait for my response, I'll just post the link to my Dropbox. This is the factory service manual for the '86 Monte Carlo, El Camino and Caprice. Enjoy.


https://www.dropbox.com/s/z36h9pfpuvzt31h/86 Chevrolet Caprice Monte Carlo El Camino SM.pdf?dl=0

 

[MrSony]

You need to talk to Doug at Quick Performance in Ames! He can get you the parts you want at a cheeper price, answer your questions, and do qout on them doing the work if you want. You should take a road trip some time and see all the hotrod stuff and thing's he offers. They do more than nine inch rearend. Did you see the 8.5 open rearend for sale on Craigslist for 700 bucks?

I had NO idea they were based in Ames! I had their site bookmarked for months!

 

[Turbo Zach]

I had NO idea they were based in Ames! I had their site bookmarked for months!

Yep you should check them out. Any thing you need to build a race car he has or can get for you. Doug was a huge help in us building dad's prostreet big block vega. A lot of custom parts went into that build. There usaly some neat projects sitting around his place. I have not been to his new location in town yet. Not open on the weekends though. If you you do build a rearend and run into trouble I can come down and give you a hand if needed. I have rebuilt quite a few differentials, from 10 bolts to Cat payloaders.