Bump for axle inspection knowledge. Anybody ever bent an axles without it breaking? Is it possible to detect that without pulling the axles?

What are the thoughts on it being a bearing? I had a really experienced ex-mechanic suggest that it may be a bearing that got screwed up. Anybody want to agree or disagree?

nobody?

Jeremy -

Did you ever have any success figuring out what this was? I have a 2nd generation (TII) with the exact same symptoms and, just like for you, it started happening immediately after I did several wheelspin launches. In case it helps you any, this is my experience so far.

The noise sounds just like a bad spot (like a bump) on my tire. Since the problem developed, I've switched tires, shocks and springs with extras I have. I've replaced the front differential mount, both rear wheel bearings, both rear axles, and the suspension bushings. Finally, I've checked the wheel rims for roundness and runout using a dial indicator. Still, it goes blump, blump, blump in the night (and day),even coasting downhill in neutral).

If I put the car on jackstands and have my son "drive" it, I can't cause the thumping to happen, so apparently the suspension must have to be loaded in order for the problem to appear.

Right now, I have my differential opened up on my work bench, and it looks brand spanking new inside--not a single metal filing anywhere to be found, and the ring & pinion show no wear whatsoever. I don't want to disassemble the differential any further, because I don't have the proper measuring tools (like a mike with a 9" span) to reassemble it correctly.

I did notice that my rear differential mounts are slightly torn, and I'm considering replacing them--otherwise I think I've just about run out of ideas. Since the blump, blump, blump frequency is the same as the wheel rotation, I'm assuming the problem lies somewhere from the ring gear to the road wheel; the pinion and everything forward are spinning at least 4 times faster than that.

Maybe all this will help you a bit. If you've found the problem, I'd appreciate it if you'd post the answer, because I'm stumped.

what was the update on this??

It is usually worn out pillow ball joints in the rear. Happened to me twice in the 25 years I have had the car. Replaced them each time and the noise is gone.
Mike

Regardless of worn pillow balls or other bushings, something has to be producing the once-per-wheel-revolution input to cause the described thumping. Do you think that normal flat-spotting caused by parking with warm tires would be enough to produce this? Or would it take something bent or dented (some sort of runout) rotating at wheel RPM to do this? I think that is the critical question since the 2007 posts found nothing bent, broken, or with measurable run-out.

I agree if it is every tire rotation. Mine and most others have described the thump on every major rear suspension travel, such as a very bumpy road or hard cornering. Then it is the pillows.
Mike

id have to say PPF as well.
you may not be able to spot cracks with the PPF installed, usually have to remove it and then you can fully inspect it properly.

Ended up being front tires IIRC. This was from 07 but I believe I had a blister on the front tire which is why swapping rears didn't fix it.

She is nice and healthy now.

Bad tires will do all sorts of weird things. It can be hard to tell if it's coming from the front or rear, typically you can feel it in the steering wheel if it's the front, and in the seat if it's the rear.

Dale