VA63SWC

Just as the weather was getting nice enough to enjoy my '63, I've developed a rhythemic one per wheel revolution thumping sound. It seems like its coming from the right rear wheel area. I've pulled the knock-off wheel and looked for obvious faults with the wheel and the brakes but couldn't see anything amiss. I only really notice it at slower speeds and it is still there in turns. I also noticed a clicking sound coming from the same area. Any suggestions. Thanks in advance.

GTR1999

check u joints and wheel bearings. Posi clutches may be chattering , add some GM additive to see if that helps- if that is the problem.

Sky65

Might be worth swapping the wheels/tires on that side front to back. See if the noise changes with it. Perhaps you have a tire problem.

splidecision63

Mine was doing the same thing. I took out the old rear end oil 90 weight, and replace it with some new. Then I add the GM additive, (works miracles) This made a beliver out of me.
Now, B4 you do all of that go to the nearest parking lot and drive you car in several figure 8's. It sounds like you rear cluches are sticking and this should break them a loose. Even if this cleares the problem I would still do the above mtce.\
\Good Luck
Geroge
PS let me know if this works.

TJefferson2020

Check to see if the ujoint is hitting on the body infront of the diff - this can be a deceiving noise but the posi theory is probably a good bet.

VA63SWC

Sucked out the old 90 weight oil and replace it with new plus the positraction additive. Same problem. Looked at the U-joints and gave them a tug and they seem tight. There is also a clicking noise that sounds like bearings but I'm not sure. The thumping is really pronounced in a right hand turn and only really noticable at slow (<25 MPH) speeds. Any more thoughts?

GTR1999

Check for worn side yokes hitting the differential. They would have over .200 wear to hit but I've rebuild a few that were hitting. If the bearing are goign bad they will feel bad all the time, if you pop the caliper up off the rotor and pull the 1/2 shaft you can rotate the rotor and feel for roughness or PB shoes catching. Is there any rust trail on the 1/2 shaft joint caps? Look at the crossmember bushings too be sure they aren't ripped, same with the front diff bushing,called a snubber.

The Black Knight

Mine started doing the same thing on a left hand turn. Jacked it up and tried to move teh tire/wheel by wiggling at the 12 and 6 positions. Nothing on the right rear, but the left rear does move enough to make the same kind of noise. I'm guessing bearings, but I'm still looking and hoping to find another reason.

blueray

Is the GM additive something specific from GM dealer or can I get at Auto Zone ... etc.? I'm having the same problem. Checked u joints, they appear to be fine. I know the diff fluid needs to be changed. I'm thinking the additive needs to be filled.

Thanks
Bryan

kenEDMUNDS

89021671 Posi fluid
1052358 Posi additive
Any GM dealer-never seen it at flaps

kenEDMUNDS

Sounds like classic wheel bearing failure. With the car jacked up and the wheel still on, grasp the tire top and bottom and wiggle in and out and check for play. If the bearing fails completely while you are driving it you will tear up the axle and the bearing housing. Big $$$, don't take a chance. Been there, done that, towed home!

knight37128

You could put your foot on tire (don't jack it up) and push hard. If you have any movement at all it's the wheel bearing. Replace them now.

PSB

Did you ever find it? I was talking with C. He found my 64 for sale for me.. He noted i should check the drive shaft yoke area in the rear for witness marks.. Great Info for sure. I kept thinking it was the rear mufflers.. But it's not.. What did you find?
Thanks

65GGvert

PSB…… that thread was 16 years ago. You’re better off if you start a new thread and explain your problem.

PSB

I saw that... Hope he found the isuue.. Mine is exactly the same. Same turn right not on left turns ect.. Thanks for letting me know.