7.5 rear diff. exchange to different housing

[mdmilburn]

i have a 1989 caprice with a 7.5 rear w/2.73 ratio . i want to use a complete differental out of a 95 s-10 with a 3.73 , what would i need to consider - if any- to retain correct side to side spaceing and pinion gear depth. i have seen magnetic base dial indicators on web sites but have not found a web site that shows the posistoning of it . has any one here done something like this (its my understanding that the caprice is a 7.5 and the 95 s-10 with 3.73 is a 7 5/8 on the account its such a big gear size)also is the shims for adjusting pinion depth between bearing and gear?

[Mr.GoodWrench]

Well, there are two ways we can do this. They right way, and the cheap way. I presume since you're using a used carrier you want the cheap way. I'm prety sure the 3.73 S truck carrier is still a 7.5 Ring gear, it should fit ok, but no guarantees.

Machining tolerances = very tight. Casting tolerances = not tight. Shims are used to make up for casting variations and obtain correct preload. Use the carrier, pinion, bearings, and races from the S-10, use the shims that are in the Caprice housing. Careful not to break the side bearing shims upon reinstallation, grey iron is very brittle and it will be a tight fit.

If you want a detailed explanation of setting up a rear end (Pinion depth, pinion preload/turning torque, side bearing preload, backlash), P/M me and I'll give you a crash course. But that will require new bearings, shims, dial indicator, marking compound etc... = more $.

[mdmilburn]

yes i,m on a tight budget and want to use every part over that i can , if there is a web site that i have not found that shows the details of such vital areas to check that would be helpfull ....maybe i will have to just check the two gears meshing with a paint or grease ?

[Mr.GoodWrench]

Paint should work okay if you're quick about it. With just the pinion in, aim for 15 lb/in of turning torque, 25-35 lb/in with the carrier in. If you don't mess up the shims for the side bearings, odds are you'll have the correct backlash, or pretty close (aim for 3-7 thou). If backlash is right, your gear pattern will be good asuming you have proper pinion depth.

[mdmilburn]

turning torque inch pounds ? are you refering to when tightening the pinion nut ? i found a illustration that shows a dowel in place for a reference point at the center of the ring still looking for something else , may consider buying a kit for around 100.00 to have for future use

[Mr.GoodWrench]

Sort of. When you tighten the pinion nut, tigthen gradually BY HAND BY HAND!!!! until all the play is taken up. If you impact it you'll over crush the collapsible spacer and have to buy a new one. Once the play is out of it, put an inch pound torque wrench on it and try to turn the pinion, note the reading as you do that. That is your turning torque. Oh and I was a bit tight on my backlash specs. For that rear anywhere from 3 to 9 thou should be fine.

[mdmilburn]

ok thanks thats a big help :)

[mdmilburn]

was at the very least going to service this rear end in my 89 caprice .i had done some research that indicated 89 was the cut off year for 26 spline axles more research today indicates that any 7.5 in a full size car will allways have 26 spline ,the f- body seems to go ether way depending on year and is 5/16 longer ( now this is whats strange i measure 30 inches from outside of flange to c -clip -there is still a small amount that could be measured. does any one know if they are interchangable? ) i would of course need a 28 spline axles that are longer than the s-10 and custom should not be the option . i know that the spider gears are uniqe to the carrier of the gears and can not be changed i suppose if i was to be in a drag race form and not worry about turning i could use a mini spool with 26 spline .i post this too let anyone know the details too consider..any one have any other ideas to fit a carrier with 3.73 gear to replace a 2.73 with out buying new gears . i know that is the clincher but i like a challenge