Differential Swap on 1981

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Nov 30, 2023 | 11:32 AM

eddp

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Instructor

Joined: Jun 2019

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Differential Swap on 1981

I am swapping the differential on my 1981. Trying to get to the shaft U-Joint is proving to be a PIA, especially with the car on jackstands.
My question is: Has anyone simply detached the Batwing Carrier and slid the diff backward with the shaft attached and then the reverse to install?
TIA.

Nov 30, 2023 | 12:31 PM

EmptyBank

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Joined: Jun 2021

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I got to the U-joint bolts with the help of an 18” 1/4 extension, going over the frame cross member and rotating the driveshaft to get all of them.

I didn’t think it was too bad, but I also have 0 rust…

If you are desperate I think you could pull it out the way you suggest, maybe. I’m not sure if the geometry will let you push the batwing down enough to get out of the frame. I would not install it that way though. That assembly of driveshaft and diff is too heavy and unwieldy.

Nov 30, 2023 | 12:45 PM

eddp

Thread Starter

Instructor

Joined: Jun 2019

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Thank you,

If I end up doing it on my garage floor, as I have done the Trailing Arms earlier this week, I can't get under it with enough room to maneuver and get angles to use the extension.

I haven't looked closely at the geometry, as I was wondering about that too.

My concern with taking it to a local shop is that very few mechanics have ever worked on an '81 corvette, so I want to give them the best instructions possible.

I've been told that finding replacement U-Joint strap bolts is becoming difficult, so I don't want to see them stripped or broken when you can't get a good angle or grip on the bolt. A shop would have multiple people and jacks to deal with the weight and balance issues.

Nov 30, 2023 | 02:06 PM

Golferdad

Burning Brakes

Joined: Feb 2022

Posts: 988

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From: South Carolina

Yea,please let me know,as I’m getting my 1981 ready,I already have a differential in the box with 3.54 gears,and I want to replace all u joints,and maybe replace trailing arms,but in a few weeks taking it to a shop to do the swap,as I to,jack and jack stands,and I’m assuming these u joints have ever been touched.good luck

Nov 30, 2023 | 02:50 PM

stingr69

Le Mans Master

Joined: Mar 2004

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From: Little Rock AR

Just need the small 12 point socket to fit (can't remember the size) and about 12"-16" or so of extensions for the ratchet. It's not that crazy. The bolts come out pretty easy. Rotate the shaft as needed for access.

Try not to overtorque on reassembly as they are rather small bolts.

Nov 30, 2023 | 04:47 PM

mikelino

Intermediate

Joined: Nov 2008

Posts: 28

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Agree with emptybank, car on jack stands, disconnect driveshaft at front yoke. Long extension with 12 point socket. Go through frame and it is actually pretty easy. Rotate driveshaft to get access to bolts.

Dec 1, 2023 | 12:33 AM

Budzuk

4th Gear

Joined: Dec 2023

Posts: 4

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I recently changed the carrier in my 80. I used a 12 pt 1/4 inch wrench to break the u joint bolts loose. Then I was able to get a socket with a long extension to finish removing the bolts.

Dec 1, 2023 | 12:37 AM

Budzuk

4th Gear

Joined: Dec 2023

Posts: 4

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With some assistance, I do believe the entire rear assembly could be removed with frt drive shaft attached. I dropped the rear carrier frame after fighting the u joint bolts.