7.5 rebuild

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ham1974

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Oct 6, 2012
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i am going to rebuild the 7.5 in my 86 montecarlo. I know everyone says don’t waste the money but I am going to try and do it on the cheap then sell it later on. I am actually going to build two rears and sell both. I have the rear in my car now which has 26 spline axles and a 3.73 gear. I have a posi for it from a late 80 early 90 trans am. I am thinking put the posi in and sale it later. I have another housing and torsion posi from a newer camaro that is 28 spline so I was going to go with it and new moser axles and a ring gear kit maybe summit brand. Thoughts?
 

ham1974

Greasemonkey
Oct 6, 2012
240
66
28
C7F9FE67-7877-4F50-91DA-455BFC978A6D.jpeg
I figure parts plus buddy doing work about $700.
 

Bonnewagon

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Sep 18, 2009
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I don't see a shim kit listed there. No new bearings for the pinion gear and the carrier? Why reuse bearings when all that other new stuff is going in? Who is doing the work? This is no job for amateurs. It takes experience and the proper tools. And after all that it is still a 7.5.
 
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Wraith

Royal Smart Person
Jan 13, 2013
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I disagree with most that speak bad about the 7.5".

I unmercifully beat a stock 7.5" with 3.73/posi for years with anything from a 225/14 to a 275/15 then to a 275/45/17 with SSM lift bars and could never kill it. John Force style burnouts. Weekly. The key to making it live is not getting it to hook like a pro stock car, this will save it. Many an impromptu exhibition of speed was won with my lowly 7.5" but I never ran it on a prepped track or with slicks.
 
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lilbowtie

Comic Book Super Hero
Jan 7, 2006
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If your throwing 300 HP or less to the rear wheels a 7.5 can handle it. Another thing is your never going to get the money you spend out of it selling it.
 
Oct 14, 2008
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People have blown the tiny posi spider gears with marginal power. I broke a no slip and exploded open spider gears. I found other stock 7.5" spider gears from an Astro Van on very limited time till boom. There is a reason the 7.625" has bigger, more even sized spider gears. Probably 225 hp but 350 ft/lbs of torque with slicks killed my 7.5".
 
Oct 14, 2008
8,806
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Melville,Saskatchewan
That late 80's Camaro posi will need 28 spline axles. Why not just add the Torsen posi with Moser axles and a girdle cover on your current rear end? It is easy, you just need to shim for proper backlash. Reuse the bearings on the Torsen posi, it they are in good shape and have the matching cups. If you want to blow money you will never get back, go for it.
 

foxtrot

Royal Smart Person
Dec 19, 2008
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In my opinion, as far as this subject goes is that you have to know your limitations. If you're not skilled in this area you will need to read & learn. This may include learning thru a few failures.

At this point in my life, I take the easier route and find a reputable builder that sells rebuilt units. I would then purchase a rebuilt 8.5 from said builder and take the rebuilt unit home & bolt it in place. Easy peasy - ha.
 
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ham1974

Greasemonkey
Oct 6, 2012
240
66
28
I don't see a shim kit listed there. No new bearings for the pinion gear and the carrier? Why reuse bearings when all that other new stuff is going in? Who is doing the work? This is no job for amateurs. It takes experience and the proper tools. And after all that it is still a 7.5.
A local race shop will do the labor for 125 plus I was figuring 75 on the other stuff.
 
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