Chirping sound coming from rear
 

Seems to be most prevalent when cold, but still barely audible when warm.

I'm not extremely familiar with the quattro drivetrain, so I don't know if this is some sign of impending failure.

Everything looked fine when I had the wheels off switching over to winter tires, so I'm kinda scratching my head here.

I know my description is kind of vague, but I'm hoping experience plays a major role and someone has had a similar experience and was able to diagnose it.

TIA

Could be allot of things, My S4 made a similar sound I think. It turned out that it was a strut mount.

What part of the rear is it coming from, how dose it happen like if you hit a bump or something, that will help allot

It sounds related to rotation, but braking has no effect. It is most prevalent at low speeds tho. As I drive and the driveline warms up, it seems to diminish, but never actually goes away. Bumps don't seem to affect it either. It's really annoying!

check your wheel bearing? have you checked your brakes as well? inside and outside pad?

It doesn't change with speed so I'm ruling out wheel bearings, and pads are good. Disc has a little bit of a lip but that's it!