How Do You Diagnose a Halfshaft U-Joint Going Bad?
A "clunking" noise developed after a track day; it coincides with wheel rotation. You can hear it in this video, ignore the static and random screeching noises, that is the camera. The noise went away on the drive home(mostly.) I put the car on jackstands and removed the wheels, everything seems tight and nothing is falling off. Put the car in gear and ran it, no noise. I think it may be the U-Joints, what should I be looking for?
When mine went bad I had the clicking noise while driving. I could see some extra play in the wheel when jacked up and turning the tire back and forth. It was hard to tell if it was bad visually. When I got the half shaft off it was then obvious it needed replacing. I could then see a small crack.
It's really hard to hear in the video. Jack it up and spin the wheels. You may be able to hear exactly where it is comming from. Spin the wheel a little back and forth and look for play while observing the U-Joints closely. If it has a lot of miles or track events I would change them anyway. They are fairly easy to replace. Consider it a little insurance to prevent you from needing a tow in. If it's not the U-Joints you will probably discover what is causing it in the process.
Go with the sealed spicer joints. A local drive line shop should be able to order them for you. That's where I got mine from. I think they were shipped over from Mississippi.
The trick is to twist the u-joint with your hands to see if there's any play in it. Sometimes you have to remove the half shaft to tell for sure. The joint could be dry, but not loose yet. Check the ones on the driveshaft too. I swear when we were at the track it sounded like it was in the trans.
Put the car up in the air. Tranny is gear on in park if auto. Move a tire forward and back while under the car and see if any of the joints have any play in them. The clunk is coming from somewhere and sometimes you need to change the direction of rotation of the wheels to see where the play is. Just running the car while in the air doesn't usually tell you much unless it is really sloppy.
Recently after an evening of drag racing at Infineon Raceway, my 87 developed a clunking noise from the rear which I had hoped was a faulty half shaft. I was able to drive it at home without any incidents which was just about 40 miles
It would only make the noise when I was making a sharp left turn.
After getting it up on a rack, discovered the half shafts and the U Joints were good.
Turned out to be a broken spider gear so looks like some major differential work awaits me.
Not saying yours is a faulty Spider gear but don't rule it out either.
Last edited by Jim McCombe; 11-12-2009 at 03:26 PM.