I now have the diff noise as well. it's been there for about two weeks and now is annoying the shit out of me. i go in and out of a 5-level parking garage every day and so it's very easy for me to hear. same exact rubbing/grinding sound.
now that i've read this thread, i feel confident that greg has identified the problem and has a fix that seems to work for him. however, there are others here that are saying to leave it alone and that the diff sound is normal. what should i do here?
i have 2800 miles on my car now and also did not experience this prior to my 1200 mile service.