Little Help

[kennels]

I have a 1970 four speed. I am getting a noise when the car is moving. Sounds like a u-joint. Does not change weather the car is in gear or the brakes are applied. When the car is on jack stands and in gear I hear no noise.
Tried walking along side of the car when wife driving(anther story) and can not tell where its coming from. I feel no movement in the shafts that lead me to believe it is a u-joint. What do I do Next?

[Ala75Vette]

Well, I'm far from an expert, but I'd check your rear bearings, just to make sure it isn't them. With the rear jacked up, grab the tire and see if you've got vertical "play" in the bearings. If you do, that's probably at least part of the problem. My bearings went out a little over a year ago, so I had them replaced. At the same time, I had my half shaft u-joints checked, and 3 of the 4 were worn out, so I had them replaced, too (good time to do it, with the bearings out). At the time I couldn't tell the u-joints were bad, but my vette mechanic showed them to me when he took them off, and they looked pretty worn out.

Frank

[dman]

insp .for rust @ u joint caps.. pos u joints starting to go,,, not loose yet.. is this a squeak / squeak// that speeds up and slows down with road speed ....???

[Culprit]

A lot of folks caution against putting the car in gear and "driving" while the rear is up on jackstands. With the rear suspention uncompressed, the angles where the half shafts connect to the rear diff and the wheels/hubs is much more extreme and can put more stress in directions that it's not meant to.

This change in the angle that the u-joints are operating at is also very possibly why you don't hear the squeak when the rear is up in the air, but you do hear it while driving.

My vote is replace the u-joints, and while you're in there test the wheel bearings for excessive in/out lateral slop - basically, if you can detect movement then they need some attention.

Semper Fidelis,
Culprit

[DDLS3]

culprit

I'm guessing that you hear an intermittent squeek or chirp when the car is moving slowly? If you are then it is most likely a u-joint. At this point there may not be any play as the joint is dry/rusted and stiff, hence the noise. See if you can determine which shaft it is and change both joints on that shaft.

[Ryan]

I had a similar problem. I Thaought it was the wheel bearings or maybe the u-joints. Idecided to change the differential fluid and also added new posi traction lube and the noice was gone. I don't know if your car has positraction, but if it does, changing the diff.-fluid is easier to do than the rest.


Good luck,

Ryan