Bad CV joint w/o clunking?

[n8marx]

As previously posted in a wheel bearing thread, my car sounds as if it's being tailgated by a train. My first thought was that I had a bad wheel bearing. I think I've ruled that out.

I performed some checks tonight after work. I drove the car and then checked each side to see if one was warm. Nope. Both hubs were stone cold. I then jacked up the rear of the car and blocked the front wheels. I rotated each wheel by hand and could not "feel" a bad wheel bearing. I then started the car and slipped it into 5th gear. I let it idle in gear with the rear wheels spinning(sounds bad but I really had it braced well). The noise didn't seem to be coming from either side. It seemed to be coming from the center of the car. For the next check I raised only the left side of the car and again let it idle in 5th. No noise. I then raised the right side of the car and did the same thing. The noise was back.

So, I have narrowed the bad component to the right side of the car, not the wheel bearing. Could a bad inner CV joint make this noise without the usual clunking? Is there a bearing in the transaxle case that might be bad?

[n8marx]

Sorry, forgot something. Could it be my differential? A previous search turned up someone who had a similar noise actually turn out to be a shot differential. While idling in gear with the rear wheels in the air I did notice that one wheel was spinning much slower than the other. Indicative of a bad differential? Shouldn't it make noise with either side in the air versus just the right?

I haven't seen the inside of a 911 differential yet but any other open-type differential I've seen was just a gear set with a set of spider gears. Nothing that should be making this noise.

Sorry for rambling. Just looking for some validation here.

[jwetering]

. If it's not your wheel bearing, and not the CV, then I'm guessing it's the bearing that the right side output shaft runs in.

I've wrecked a few of these in an old toyota 4x4 I used to run. It's sometimes called a "carrier" bearing.

You know what you have to do to eliminat ethe CV eh...either swap one shaft for the other, or just check to see if the noise persists when the shafts are out altogether.

That would be safe, that's for sure.

[Tyson Schmidt]

If it were a bad differentila carrier bearing, it would make noise with either wheel off the ground. They both spin so long as the ring and pinion are spinning.

Do yourself a favor and remove the right axle, caliper and rotor and spin the hub with out all the parts attached. Trust me, it is very possible to have a bad wheel bearing that is bad but not noticeable with all the axle and brake parts attached. I do this for a living. I see many many many of these cars every day. I've found many a bad wheel bearing that passed all the initial tests, but were found to be bad once I tore them down to just the hub and bearing. John Walker told you the same thing. Just try it.

[n8marx]

Thanks for the help guys. Ordering a pizza tonight and partying with the Porsche. You've convinced me. Drop the shade-tree mechanic's diagnostics and just tear into it properly. More later.

[mussberger]

What did you find wrong?

[n8marx]

Bad wheel bearing. I mean a REALLY BAD wheel bearing. One half of the bearing seized. As a result my hub was spinning inside the bearing race. The loud noise I was hearing was my hub being ground away into nothing by the seized bearing. A new bearing and a replacement hub solved my problem.

It is interesting to note that every one of my wheel bearings failed at roughly the same time. My first bad rear wheel bearing surfaced at about 94k miles. I now have 99k on the car and every wheel bearing has been replaced due to noise.

[mussberger]

Thanks,

I have a rattle that comes and goes thats driving me nuts but I don't think it is the wheel bearings

[n8marx]

I agree. I don't think a rattle would point to wheel bearings.