Rear end or tranny problem?

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Apr 19, 2008 | 08:10 PM

Keystring

Thread Starter

Drifting

Joined: Aug 2006

Posts: 1,624

Likes: 2

From: Canandaigua New York

Rear end or tranny problem?

I'm having an issue with my 84 vette.

I've been working on restoring this car and ran into a problem recently when I tried to move it.

It acts like it is stuck in {Park} but the shifter is disconnected and I can move the gear lever by hand so it's not stuck at the tranny.
So, I decided to jack up the back and check to see if the brakes were froze up.

Nope.

The wheels turn. BUT, when I turn one 'Forward' the other turns 'Backwards'. Now I know a standard rear end will do this but I was under the impression (from everything I've read) that with a 'Posi' unit, both wheels are supposed to turn in the same direction.

Update:

It seems the drive shaft is not turning when turning the wheels by hand, which seems to indicate the trans is stuck in park.

Any ideas,short of pulling the trans apart, on how to free it up?
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I'm trying to get this car in my 'new' garage to work on it and it is very frustrating because it won't roll.

It just doesn't seem to want to cooperate with me.

Last edited by Keystring; Apr 20, 2008 at 11:25 AM.

Apr 20, 2008 | 11:27 AM

Keystring

Thread Starter

Drifting

Joined: Aug 2006

Posts: 1,624

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From: Canandaigua New York

Apr 20, 2008 | 11:30 AM

Deakins

Burning Brakes

Joined: Sep 2005

Posts: 993

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From: Iowa

Well if you just need to get it to move you can just take the drive shaft out of it and roll it in that way... If you can move the arm on the transmission by hand and that doesn't work then something will need to be done inside the transmission to get it disengaged..

Apr 20, 2008 | 11:32 AM

Keystring

Thread Starter

Drifting

Joined: Aug 2006

Posts: 1,624

Likes: 2

From: Canandaigua New York

I though about removing the drive shaft, until I saw what it's going to take to do it.

Oh well, guess I don't have a choice.

Thanks

Apr 20, 2008 | 12:15 PM

CFI-EFI

Race Director

Joined: Sep 2000

Posts: 17,298

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From: The Top of Utah

Quote:

Originally Posted by Keystring

I though about removing the drive shaft, until I saw what it's going to take to do it.

Oh well, guess I don't have a choice.

Thanks

The wheels turning in opposite directions indicates the posi traction clutches are worn out. There could be something broken in the trans that prevents the park pawl from disengaging, or the ring and pinion in the differential could be locked up. Even though you don't like the prospect of removing the drive shaft, it is the first step in removing either the trans or differential for repair.

RACE ON!!!

Apr 20, 2008 | 12:21 PM

Aurora40

Le Mans Master

Joined: Apr 2005

Posts: 6,413

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From: The Old Dominion

If the driveshaft doesn't rotate, shouldn't that prevent the wheels from rotating either, assuming the diff were working properly?

You said you can rotate the wheels, but the driveshaft doesn't move. That sounds pretty weird to me.

Apr 20, 2008 | 01:09 PM

CFI-EFI

Race Director

Joined: Sep 2000

Posts: 17,298

Likes: 33

From: The Top of Utah

On a non posi traction diff, the rear wheels will turn in opposite directions without the drive shaft turning. That is normal. With posi, both rear wheels should turn the same direction, but only if the drive shaft is free to turn. With the drive shaft locked (IE trans in park) neither rear wheel should turn at all. A posi diff with worn out clutches reverts to normal, non posi operation.

RACE ON!!!

Apr 20, 2008 | 01:41 PM

Keystring

Thread Starter

Drifting

Joined: Aug 2006

Posts: 1,624

Likes: 2

From: Canandaigua New York

Quote:

Originally Posted by CFI-EFI

You're right. I do need to remove the drive shaft, but I was hoping I could get it in the garage first instead of working in my muddy yard.

I plan on rebuilding the tranny anyway, but I had the garage built just to avoid the problems of rolling around in the dirt and mud.

Thanks for the insight on the clutches..It was my first thought as well because of the opposite rotation of the wheels, but I really wasn't sure.

Don't really know what happened to lock it up because it rolled fine before I pulled the engine. After I installed the new one is when it wouldn't move..The torque converter isn't bolted up to the flywheel yet, so I don't think that is an issue.

Time to roll in the mud I guess.

Thanks.