rear end groan when turning
Thread Starter
Navigator
Joined: Nov 2004
Posts: 9
Likes: 0
From: Tampa FL
rear end groan when turning
Can anyone help here. I recently purchased my 79 and love her but when I turn I hear a low groaning from the rearend. The differential was replaced within the last year or so. I know the leaf spring is shot and have one ordered. Any ideas? It is like a mmmmeeewwwoooa noise which goes away when you drive straight.
Burning Brakes
Joined: May 2001
Posts: 1,127
Likes: 3
From: syracuse ny & venice fl when snowing in ny
u better hope the post above mine is correct. cause it sounds like a wheel bearing!
have fun! REAL expensive and only experts should tackle this! a c4, you can do by yourself, not so with c3's
hope i am wrong!
have fun! REAL expensive and only experts should tackle this! a c4, you can do by yourself, not so with c3's
hope i am wrong!
Le Mans Master
Joined: Apr 2000
Posts: 7,562
Likes: 9
From: B'Ville NY
Cruise-In III Veteran
St. Jude Donor '05
You can try stopping buy your local Chevy dealer in purchasing 2 bottles of posi additive and add it to your differential case to lube you posi clutches. This is not that expensive (~$12) and is easy enough to try 
Burning Brakes
Joined: Nov 2004
Posts: 1,193
Likes: 176
From: Hillsborough NC
Definitely try changing the rear gear oil and posi additive first. It's cheap and it does wonders.
I had a similar issue with my 78 and could swear it was a muffler banging. Only did it while accelerating and turning.
I changed the rear oil and put in new additive, drove slow tight circles for ten minutes in one direction, and then the other and it is smooth as silk now. Sure got some funny looks at the local Wal-Mart while doing the circles though....
Here's hoping it's simple!
I had a similar issue with my 78 and could swear it was a muffler banging. Only did it while accelerating and turning.
I changed the rear oil and put in new additive, drove slow tight circles for ten minutes in one direction, and then the other and it is smooth as silk now. Sure got some funny looks at the local Wal-Mart while doing the circles though....
Here's hoping it's simple!
Le Mans Master
Joined: Aug 2003
Posts: 7,720
Likes: 12
From: Chattanooga TN
Originally Posted by SmokedTires
You can try stopping buy your local Chevy dealer in purchasing 2 bottles of posi additive and add it to your differential case to lube you posi clutches. This is not that expensive (~$12) and is easy enough to try
most any GM dealer should have it.
Le Mans Master
Joined: Aug 2000
Posts: 6,362
Likes: 7
From: Brazos TX
Cruise-In IV Veteran
Cruise-In V Veteran
Yep, the same thing happened to me. Adding the posi lube and doing the tight turns will fix the problem. I went with Mobil 1 synthetic gear oil but the GM stuff obvioulsy works fine as well.
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Thread Starter
Navigator
Joined: Nov 2004
Posts: 9
Likes: 0
From: Tampa FL
groan fixes
I want to thank everybody for the ideas. I have ordered a new leaf spring / mounting hardware. I will buy the posi additive. Can you add too much additive? Is there a way to check the current level? The guy with the wheel bearing has me scared because I will have to learn to do it myself anyway. Expensive is not an option at this point. Thanks again for starting places. 
Burning Brakes
Joined: Jun 2002
Posts: 837
Likes: 3
From: Texas
The additive is GM # 1052358.......a 4oz. bottle. I added 1 bottle to mine when I changed the fluid. I've heard some people add 2 bottles. The fluid should be filled to the "level plug" on the side of the diff. I would suggest taking it to a lube place that has a suction pump (since these don't have a drain plug)....have them pull all the old fluid out....add the bottle of additive....then top it off with new GM diff. fluid.
