hudsonfowler

My 95 90Q with 75k started producing a weird sound from the driver-rear wheel well. It is at it's loudest around 60/65mph and sounds like someone's running a weed whacker off in the distance but it's definitely coming from the left-rear. It's kind of a "distant outboard boat motor" kind of sound. The pitch increases with speed and is eventually drowned out by road noise but it's still pretty loud. Could be a bad wheel bearing?

Thanks

KidoSenkan

Yours is an AWD? It could be the wheel bearing, i don't know how a faulty differential sound like. The left front bearing of my 80 sounded like a hollow roar at 35-40 mph, noisiest car ever. sorry, not much help

Seattle Scott

CV Joint? Try going forward in tight circles both left and right.

Mancubus

What's the cost of replacing the wheel bearing? I think I have a similar problem with my driver side bearings. When I go over 40 km/h the whining changes pitch. What problems would I be facing by driving with bad bearings?

SteveAngry

You could wear out the hub, tire could fly off, etc...when it starts to make a grinding noise get it repaired soon. It'll save you $$.

As far as pricing goes... $160.00 for the front and $100.00 for the back. This was for a non Quattro 88 5000...Your cost may vary. Of course, changing them yourself will save you money...

Steve Ankney
88 5000
Michigan

Mancubus

How hard is it to replace? Any special tools required?
Also, how do I test to ensure which ones need replacing. I originally thought the sound was coming from the speedometer but after driving with my window down I can hear it coming from the front somewhere, possibly the driver side front wheel. Are there any visual cues that could point to a problem? Thanks in advance.

SteveAngry

I personally did not do the work on either of mine. Both were during the school year and I didn't have access to tools or a garage. My front WB made a humming sound on the way home from a concert. By the time I got home it was "grinding." I could definitely tell which one it was! However the back one was a little different. I had a tire back there that was somewhat out of round and made a slight humming/whirling sound at speed. One day as I was driving home from the movies my back drivers side wheel starts making a terrible grinding noise. I thought that the caliper had stuck. Turned out that it was the wheel bearing. I think the noise from the tire had masked the sound of the wheel bearing for awhile. Turned out that the bearing had gotten so bad that it had slightly shifted the hub so it was rubbing aganist the brakes. Not good.

Most times you can tell what side the noise is coming from by turning one way or the other. A bad WB should make itself known when you start turning. If that does'nt work have a friend drive your car while you walk/run next to it...listen while he turns/drives...

HTH
Steve Ankney
88 5000
Michigan

Mancubus

The problem that I have is that turning makes no difference in pitch at 2mph or 60mph, the sound just seems to increase in volume and pitch the faster I go. It also seems to be getting louder, i.e. what it used to sound like at 70mph it now sounds like at 40mph and of course, it just gets worse the faster I go. To me it seems like it's coming from the driver front wheel, but I can't trust what I hear from inside the car since for the longest time it sounded like it was coming from the dash. Not that I'm an idiot or anything but it's winter so I only drive with the windows up all the time. The only sound that actually gets inside the car must be through the steering column which would account for my mistaken assumption. I confirmed that it was actually coming from the wheels by driving beside parked cars going 40mph. Everytime I drove past a car the sound amplified due to the reflection. Even with the windows down it's still questionable that it's coming from the wheels until it's confirmed by the reverb from the parked cars. The question remains wether its the front or rear driver side or front and or rear passenger side. I just hope this doesn't cost me an arm and a leg.

Any suggestions on how to confirm my problem would be GREATLY appreciated.

Mancubus

I just got back from taking the car to a non-Audi (but competent) mechanic friend of mine. He drove my car and concluded that the problem is not the bearings as he stated that there are no drivability symptoms that would attribute to that, i.e. vibrations, grinding etc. When we got back to his shop he put the car on the hoist with me in it and had me do 40mph free wheeling while he checked the drivetrain. He concluded that the noise is coming from the front differential. He's not familliar with the Quattro system so he could not speculate beyond where I should start looking. My quesion to you guys is what do you think it could be? Wild guesses are welcome as they would be better than anything I can come up with. Is it possible that a low fluid level could cause this? Is there a way to check the fluid level? How easy is this to replace?

KidoSenkan

Ok i'll let you know what I can on the bearings. Mine cost $80 for the left front, $20 to press it in(according to the mechanic, you *need* to press it with some kind of machine or you'd ruin again very quickly) plus labour it came up to about $150.

if you think the AWD differential is busted, i can't help you. anyone knows a good online source for drivetrains especially on trans and suspension? preferably an encyclopedia or something like that.