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Topic: Rear end noise

in Forum: C3 Driveline Components


Rear end noise

Posted: 10/1/09 1:44pm Message 1 of 7
Former Member
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Robersonville, NC - USA
Joined: 4/23/2009
Posts: 47
Vette(s): 76 stingray

Hi all,

Ok here is my delima. I am still working on the Vette before I put it on the road. Well I was checking out the rear brakes and rear suspension. I decided to crank it up and let the rear wheel turn. Well there was a thunk, thunk thunk noise coming from the rear end. The right rear rotor is warped so I too it off to see if that might be it. Well it wasn't! (surprise) Then I thought, well let me take the half shaft out and see if it still does it. When I did this the noise went away. The u-joints seam to feel pretty good. Nice and smooth through all positions and movement. The ony thing that I can think now is it is in the Trailing arm. The bearing maybe? It doesn't seem to feel bad or have any free play in it as I can tell. It is a little hard to turn though. (stiff) I didn't do anything to the driver side, but I did notice some vibrating (movement) as the rear end turned it.  What could this be? Is this something a trailing arm could do? Could it be the rear end? I hope not!
 
Please help me out here. I need to get it fixed, but don't want to be spending anymore than I have to right now.



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Rear end noise

Posted: 10/1/09 6:02pm Message 2 of 7
Lifetime MemberLifetime Member
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North Charleston, SC - USA
Joined: 3/20/2004
Posts: 4176
Vette(s): 1975 L48 AT AC T-top
If I an reading this correctly it sounds like you had the car on a jack or jackstands with the rear wheels clear of the ground. You had the car in gear with the rear wheels turning. If this is the case and the trailing arms were not supported, then both half shafts were suspended at angles far beyond the norm. This puts excessive loads on the u-joints and yokes. That's why you didn't hear it when you removed the shafts. I would not reuse those u-joints. Hope this helps.
Scott



Rear end noise

Posted: 10/1/09 6:28pm Message 3 of 7
Former Member
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Calhoun City, MS - USA
Joined: 9/24/2005
Posts: 121
Vette(s): 1977 Black T-Top
As Ranger have stated. You're not dealing with a Solid  Axle car.  Your load is riding on those U-Joints. When you jack it up.


Rear end noise

Posted: 10/1/09 7:10pm Message 4 of 7
Former Member
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Robersonville, NC - USA
Joined: 4/23/2009
Posts: 47
Vette(s): 76 stingray
You are right. I have the car up on jack stands. I thought about that also (u-joints being at to much of a angle) but wasnt sure. What I dont understand is, I took out the right half shaft, the left is still in the car, and the noise is gone.   
Thats cool, I was planning on replacing the u-joints anyway.
Thanks for your help.



Rear end noise

Posted: 10/2/09 9:51am Message 5 of 7
Former Member
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Old Hickory, TN - USA
Joined: 5/26/2003
Posts: 599
Vette(s): 1978 L-82 Silver Anniversary hotrod. /////////////
While you have the ass end in the air, replace all 4 u-joints. There is no such thing as one bad axle u-joint on a C3 'Vette.... about 20 bucks apiece at Advance Auto Parts..

Dave


Rear end noise

Posted: 10/2/09 1:42pm Message 6 of 7
Former Member
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Dutchess County, NY - USA
Joined: 8/27/2007
Posts: 2484
Vette(s): White '79 Corvette. It's a driver.
While you're back there, you may want to change the rear diff. fluid and add some GM Posi Lube Additive.
Even if it's not the cause of the (U-Joint) noise it's a good piece of insurance for the rear diff.
Cant hurt.
Kevin



Rear end noise

Posted: 10/2/09 6:04pm Message 7 of 7
Former Member
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Robersonville, NC - USA
Joined: 4/23/2009
Posts: 47
Vette(s): 76 stingray
Is there a way to check the bearings in the trailing arms?  The bushings on the arms are shot so it kinda hard to tell if there is any movement in them.  I recken what I am asking, is how would I know if they need replacing. Madrider2009-10-03 05:38:58


in Forum: C3 Driveline Components


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