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Topic: Rule of thumb on Diff rebuild

in Forum: C3 Driveline Components

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Rule of thumb on Diff rebuild (1/8)
4/22/08 9:49pm

77 Red Corvette
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Joined: 3/23/2008
Posts: 81

Hi,

My 77 Vette has about 52,000 original miles on it. My husband and I just pulled the rear Diff and it has been leaking a little. We didn't have plans to rebuild it but after the job it has been pulling it out we never want to have to do it again.

I was wondering what the rule of thumb is to having it rebuilt or not. What should we look for within the Diff itself that would lead us to go ahead and rebuild it. Tomorrow we plan to take a real close look at it.

We have bought a better heavy duty cover, new yolks along with the kit to drill in a drain so that the Diff fluid can be changed easily in the future.

Any advice would be very helpful!

Thanx,

Anni ... 77 Red Corvette

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Rule of thumb on Diff rebuild (2/8)
4/22/08 9:51pm

VetteSpecialties
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Unless abused, those differentials tend to last 100,000 miles or more. I wouldn't change anything that didn't show wear. The HD cover is always a good idea.

Larry

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Rule of thumb on Diff rebuild (3/8)
4/22/08 9:56pm

77 Red Corvette
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Posts: 81

Thanx Larry,

That was the news I was hoping for! That's great that they last that long. But of course I will give it a good once over to make sure that nothing looks worn out.

Anni ...77 Red Covette

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Rule of thumb on Diff rebuild (4/8)
4/22/08 10:16pm

Adams' Apple

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At least put new seals in it while it's out. Check the ends of the old yokes for wear, as they have a tendency to do. If they have major wear on them, you'll want to check the pinion shaft also.
As long as the diff was not making any noises, it's prolly ok.
Be sure to put in a couple of bottles of posi-lube and finish with gear lube before re-installing it. It's much easier to put that stuff in on a bench than it is with the diff in the car.

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Rule of thumb on Diff rebuild (5/8)
4/22/08 10:25pm

cthulhu

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check to make sure that you have plenty of room past the snap ring on the inside of the yokes... I dont remember what the spec is... but i think it is around 3/16ths

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Rule of thumb on Diff rebuild (6/8)
4/22/08 10:49pm

Adams' Apple

Good point, Ben!

Take a look at these pics...the wear on the ends of the yokes will make the yokes have too much clearance, and cause the rear alignment to change as the wheels move side-side.
Since you're installing new yokes, this won't be an issue, but you do need to verify the free-play of the yokes...there should be none with them installed.

Click for link

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Rule of thumb on Diff rebuild (7/8)
4/23/08 11:40am

corvette440hp

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I don't know how versed you and your husband are, but hopefully you have a dial indicator to be checking things out. As Joel mentioned you will need new seals (inexpensive). Be careful when installing the seals. You will also need angled snap ring pliers to get the snap rings off of the axles.

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corvette440hp

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Rule of thumb on Diff rebuild (8/8)
4/23/08 10:23pm

77 Red Corvette
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Posts: 81

This evening we pulled out the diff and took a good look at it. Things look very good. However we will replace both yolks and all the seals. We have a dial indicator along with those special pliers, my husband is well versed thank goodness

The next few days I will spend cleaning everything up before we start to put things back together again.

Oh we did find evidence of a mouse that had at one time made a home in the crossmember bar!

Thanx again for everyone's great advice!

Anni 77 Red Corvette

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