80' differential rebuild
Thread Starter
Advanced
Joined: Dec 2006
Posts: 50
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From: Houma La
80' differential rebuild
The rear is a Dana with 3.07 gear. I don't see anyone jumping at the chance to rebuild one of these, why is that? Also, where would I get good parts to rebuild it myself?
Thanks,
Stephen
Thanks,
Stephen
Safety Car
Joined: Oct 2006
Posts: 3,930
Likes: 15
From: Calgary Alberta
The 1963-1979 differentials were iron units - these are a lot stronger then the diff's after these years. GM decided to swap the casing to aluminum to save weight after 1979. Thus, the aluminum units are a lot weaker than the iron ones. If you plan on running a lot of horsepower through your car in the future, I suggest you research on how to convert your unit to an iron unit. I've seen it done before.
Racer
Joined: Mar 2006
Posts: 291
Likes: 0
From: Guantanamo Bay, Cuba (home in Colorado Springs)
tracdogg2 (mike in TX) can rebuild these. The 80-82 rear end was not a stunning design effort. The 3.07 gear is designed for economy. You can have them rebuilt with down to 3.73. You may even be able to do 4.11, although, I don't know why anyone would use that low of gear in this type of diff. Rebuild services are offered by several vendors in a core exchange; you send them your old diff and they send you another rebuilt unit for about $800 on up. Rebuild kits vary in $$ depending on what all needs replacement, new or refurb yokes & gears, etc.
Bear in mind when doing diff work, the auto & manual trans types used very diffrent yokes (stub shafts).
Bear in mind when doing diff work, the auto & manual trans types used very diffrent yokes (stub shafts).
Safety Car
Joined: Oct 2006
Posts: 3,930
Likes: 15
From: Calgary Alberta
I suggest you give gtr1999 (gary) a shout. He builds the best differentials out there for c3's. The iron diff will bolt up the the batwing with very little modifications. He tunes the posi unit, installs full clutches, polishes the posi case, installs new bearings, the works.
Burning Brakes
Joined: Aug 2006
Posts: 1,155
Likes: 0
From: San Diego California
I believe Mid America and probably some other catalogs sell the rear diff, with or without your core exchange- and the 80-82 rear is plenty strong for a mild- moderately hot rodded strret car.
Pro
Joined: Jun 2001
Posts: 672
Likes: 0
From: Quebec
I found out that the bad reputation of those aluminium differential comes from bad aluminium casting. The 84 and up used almost the same design (Dana 44) with some improvement but have far better aluminium casting and are rated for a lot of abuse.
You can rebuild yours with a richmond gear from 2.72 to 3.73 (or 3.90), new bearings and new cluthes for around 500$. If you want 4.11 and more, you need to change the posi unit.
I'm running close to 400 hp, manual trans and street tire with no problem so far...
The secret is the case, check it for bad casting and cracks as this one...
You can rebuild yours with a richmond gear from 2.72 to 3.73 (or 3.90), new bearings and new cluthes for around 500$. If you want 4.11 and more, you need to change the posi unit.
I'm running close to 400 hp, manual trans and street tire with no problem so far...
The secret is the case, check it for bad casting and cracks as this one...
Last edited by American Boy; Feb 26, 2008 at 12:30 PM.
Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
If you plan on any significant power upgrades, I'd follow stinger12's advice, go with an iron unit. That's one of my '81's current projects, I don't think the stock unit will last behind an LS 427 for very long, at least with my foot on the loud pedal.
Racer
Joined: Feb 2007
Posts: 337
Likes: 1
From: Clyde Ohio
I'm doing my 82 right now. I bought the clutch pack and seals from Duntoff, the Timken bearings from AutoZone, shims from Ratech. Parts were cheaper than buying a kit. You will need access to a press or bearing puller to set up the carrier bearings. The pinion shims are actually behind the head race for the pinion. If your carrier preload is tight you MAY need a case spreader (I set mine up and didn't need a spreader). The carrier can safely and properly set up without the spreader though so don't let that scare you. If you want to attemp this or have any questions contact me. This is basically the same (except aluminum) rear that is used in thousands of Jeeps so there's alot of similar info if you do a search.
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Safety Car
Joined: Nov 2004
Posts: 4,359
Likes: 57
From: Mundelein Illinois
I suggest you give gtr1999 (gary) a shout. He builds the best differentials out there for c3's. The iron diff will bolt up the the batwing with very little modifications. He tunes the posi unit, installs full clutches, polishes the posi case, installs new bearings, the works.
Gary doesn't rebuild 80 - 82 but he did reccommend someone on the forum that does. I sent mine to Bair's and they did a great job.
Safety Car
Joined: Oct 2006
Posts: 3,930
Likes: 15
From: Calgary Alberta
Aaaaah, but Gary works on iron diffs. I asked him if there was a conversion for the aluminum diffs and he said that the iron unit would bolt up to the bat wings with very little mods, so converting to an iron unit wouldn't be all that hard.
Pro
Joined: Nov 2007
Posts: 741
Likes: 1
From: Woodstock GA
Drifting
Joined: Oct 2004
Posts: 1,496
Likes: 1
From: Lafayette Louisiana
Tracdogg2 does the 80-82 units. Look him up in the member list and pm him. I have his card at my office if you need the number let me know.
Here you go. http://classiccorvetteparts.vstore.ca/
Good folks!
Here you go. http://classiccorvetteparts.vstore.ca/
Good folks!
Last edited by kevinator80; Mar 6, 2008 at 09:03 PM.
Pro
Joined: Nov 2003
Posts: 692
Likes: 1
From: Peabody Ma.
Let me know if you find some to rebuild one, Im geting ready to order my parts, swapping out for 3:55 gears. I found all the parts, I cant find any quality bearings local, I may have to buy them from the distrubter for a premium of course! I set it up my self if I have to
Instructor
Joined: May 2021
Posts: 127
Likes: 28
Is there anybody in Minneapolis area that can do a differential rebuild for a 74? Mine definitely needs a rebuild and now it leaks. So it needs to be done sooner than later. Everybody is so busy, I may need to buy a new one and send in the old as a core.
