928scubadude

How do you check a cv joint. I get a clunk from the rear when I down shift with my auto trans at slower speeds. Driving forward even under heavy acceleration it shifts great. I had the tranny fluid and filter replaced and still same noise.

I jacked up the rear wheel with the car in park and I get movement and a clunking sound. My other rear axle was replaced last year.

I have 112000 miles on m 87 s4.

Thanks

SharkSkin

If you can put the car up on ramps or a lift that keeps the suspension in normal road position(like this) then you can reach up under there and give the shaft a wiggle, preferably with the parking brake on and trans in neutral. If you jack the car up, the shaft sits at a different angle than when driving which may mask a problem. I recommend some leather gloves for this as well.

Normally, you should be able to move the center shaft back and forth along its axis. But ideally it should move in a tightly controlled fashion, meaning it doesn't have any play when you try to rotate the axle. Move the axle in and out of the joints slowly while you try to rotate back and forth. If you find that at some point it has a lot of play, enough to be clunking when you move it by hand, then the axle side joint is toast. Be sure to properly identify the clunking that occurs when the shaft is at the end of its range of in/out travel... don't mistake that "OK" sound for excessive play in the joint.

To check the trans side joint, again move the axle shaft in and out of the joint, but this time rotate the axle in one direction and hold it there while doing so. Reach up with your other hand and try to rotate the joint back and forth, and see if you can detect any play between the trans side joint and the axle. Again you want the joint to be tight. Since the trans should be in neutral, you should be able to get a pretty good feel for the condition of the joint. Pay attention here, and be aware that backlash in the trans can confuse the issue, making clunking noises that are perfectly OK but throw you off the scent.

If the boots are split or ready to split, they should be replaced as a minimum. CV joints usually last as long as the boots, because once the boots go the joints dry out and fail quickly.

Early model halfshafts can be rebuilt without removing the wheels. Your car probably has the outer joint welded, in which case you need to pull the nut off of the splined shaft that goes through the knuckle. Tony has a great writeup on his site explaining how to remove and re-install the later halfshafts.

928scubadude

Thanks Sharkskin, I will give it a try this weekend. I had to remove my bbs wheel because it has a little crack and it is leaking air. Luckily there is a guy here who will weld it for me.