ams

I have a 2001 A4 Quattro with 190k miles (getting up there, I know). The last few months I've observed a very loud/pronounced grinding noise on hard long radius right-hand turns coming presumably from the rear drivers side of the car.

I had drivers side rear wheel bearing replaced and no difference. I also changed the rear diff fluid and no difference.

A few observations:
- it only happens when the car is fairly 'loded up' in a turn. In one of these long turns if it is easy, no noise, if I jerk the wheel a little tighter it comes full on.
- it 'appears' to only happen under power/accel. I was coming down a windy mountain pass and when I put it in neutral or clutch in I can take sharp fast corners as hard as I can and everything is super quiet. But if i try and accelerate through similar corners it happens.

I've done a lot of searching and for similar symptoms the diagnosis is usually wheel bearings or rear break pads/calipers rubbing, but this doesn't appear to be my case.

Thinking maybe rear diff?? I've never really read a thread where someone's rear diff actually went bad or had to be replaced (other than leaky seals).

Thanks!