Hi guys,

I've read all of the threads (that I could find in a search) and although some are close, none of them describe my issue close enough to consider it the same.

I have a short, intermittent, low pitched grinding noise coming from (what I believe to be) the right rear at takeoff from first gear. It sounds like it's coming from the RR wheel bearing, but I've never had to deal with Quattro wheel bearings before, so IDK.

If I launch hard enough (and I don't mean side stepping, or WOT), it sounds like the power (torque) is being transferred to that wheel (which makes sense) and it's too much power for something to bear, making it grind a bit.

It reminds me of when I had (big) drum brakes on my '66 Pontiac. The rear shoes would stick and when I pulled off from a light, they would "ping" when they broke loose. This has the same timing, but a much different sound.

I just changed the gearbox/front & rear diff fluids. No change in the issue and no metal in the oil. I know the rear pads are at end of life, but the warning clips aren't making any noise yet, so I doubt that's the issue (although I suppose it could be).

My guess seems to be a simple wheel bearing issue (it's dying), but I don't know that, so I thought I'd ask, because I'm sure someone has gone through this before.

Thanks in advance

 

No idea myself, but my two guesses would be wheel bearings (as you mentioned) or brakes are sticking (as you also hinted at).
If you can do the two rear bearings yourself, great. Sounds like they need to be done anyway so it wouldn't be a loss if the sound returned.
A quick check on the brakes by lubing the slide pins would take only 15 minutes or so.

Otherwise, 9 times out of 10 when I work on my car and a new sound immediately arises, it's because I managed to completely screw something up. Not sure how, but could you go back and check the levels of the fluids? Could you not have quite filled them all the way? That would probably be the most critical of the three issues I'm guessing.

 

The fluids are fine and although I do the vast majority of my own work, I'm also good at knowing what I shouldn't be doing myself and unfortunately, the bearings are one of those things. I'll be replacing the pads and rotors soon enough, so we'll see about that, but like you said: I would love to change at least that bearing, as it couldn't hurt.