Rear End / Differential Issues
Thread Starter
Burning Brakes
Joined: Sep 2005
Posts: 1,139
Likes: 109
From: B'ham Alabama
Rear End / Differential Issues
My rear end / differential has started making a growling sound at low speeds and sharp turns. I fear the worst. Do I have a rear end going bad? Is this a common problem? What is the remedy, if any, other than a replacement?
If I need a new differetial, how expensive is this problem and where do I get one?
My car is a stock 1976 L-48 with automatic.
If I need a new differetial, how expensive is this problem and where do I get one?
My car is a stock 1976 L-48 with automatic.
Melting Slicks
Joined: May 1999
Posts: 2,897
Likes: 0
From: Moon Township PA
It costs you very little to drain and refill your differential with new fluid and new GM positraction additive before you throw money at a rebuild.
Drive your car for a few miles to warm the diff lube up. Suck it out with a suction gun and refill with your favorite diff lube and one bottle of GM Positraction Additive. Drive your car to the nearest big parking lot and drive slow figure 8s forwards and backwards to get the lube into the positraction clutches.
Btw, put the GM stuff in first and fill your diff until the lube runs out. Should take just shy of two quarts.
Tell us the results.
Gary
Drive your car for a few miles to warm the diff lube up. Suck it out with a suction gun and refill with your favorite diff lube and one bottle of GM Positraction Additive. Drive your car to the nearest big parking lot and drive slow figure 8s forwards and backwards to get the lube into the positraction clutches.
Btw, put the GM stuff in first and fill your diff until the lube runs out. Should take just shy of two quarts.
Tell us the results.
Gary
Le Mans Master
Joined: Jan 2000
Posts: 8,918
Likes: 27
From: New Hill NC
You should check it for wear in the side yokes. If they are bad you will see where the U bolts are hitting the housing. This is a very common problem beginning with the 75 and epidemic by 78.
Tech Contributor
Joined: Aug 1999
Posts: 15,188
Likes: 4,010
From: Connecticut, USA
Common problem, as stated, with the yokes. '76 uses a weaker type of clutch too so you may be getting clutch hammer, groaning could be pinion bearing.
I would look it over and check for endplay in the yokes. If it is under .050" per side then change the oil add the Gm additive and see if that helps. If not then you can live with it for a while or drop it out and open it up.
Look over this post it will help you understand what's involve in there.
http://forums.corvetteforum.com/show....php?t=1236684
I would look it over and check for endplay in the yokes. If it is under .050" per side then change the oil add the Gm additive and see if that helps. If not then you can live with it for a while or drop it out and open it up.
Look over this post it will help you understand what's involve in there.
http://forums.corvetteforum.com/show....php?t=1236684
