This is the first winter with my quattro and I've got a new problem. Whenever the road gets slippery from slush etc the car's back end sways back and forth and the steering sort of leans into the slide to compensate ... like if my rear end starts going right on me, the wheel turns right as well.

I don't think it's a tire/traction thing... my car accelerates and brakes just fine, in fact my girl pointed out that it only starts to sway when I finish accelerating and cruise.

What should I look at first? I'd think it might be a 4WD or differential problem, but I've read it might be rear suspension as well.

 

Had my car in the shop a week ago, the rear wheels had been left badly mis-aligned - like 1.5" - by the mechanic who had done some work on the tie rods and stuff back there... so every time my traction wasn't exactly equal on the rear the back of my car would shove one way or another.

It's totally sorted out now and I'm pushing old man winter down the stairs whenever he throws bad roads at me, like a proper Audi owner.

 

Post up some pics of the coupe. My son has the same car.

 

Is my transmission supposed to sound like a dentist's drill?

There's like a high-pitched weeeee sound from the back somewhere while I'm driving, I agree with the sentiment but I don't know if the car should be that loud about it.

 

How far to the rear of the car is the sound coming from? Maybe check the rear diff. If you don't know when the fluids were changed last, I'd drain all the diffs and tranny, and put in some fresh fluid. On a car that old, I wouldn't be surprised to see some pretty nasty fluids come out...

And yeah, post some pics!