I have been dealing with this for months now. I guess that they don't want to honor their warranty. However, I have been told at my dealership that I'm the only one with this problem that they have seen and are stumped at how to fix it. I have a whole thread on my sad story in the "service" section here.I was told by customer service that GM feels that this annoying rattle doesn't affect the use of the car and that they aren't going to do anything about it. Why? I am sure that after 3 years of complaints that GM knows what the problem is but doesn't want to pay for repairs. If so, at least tell us so we can fix it ourselves. It has turned a good car into an annoying one that I can't wait to get rid of.