KC-BG

That's exactly how I described it at times....as if two incredibly loud pieces of Styrofoam were being rubbed together. I was told it on the driver's half of the firewall but I do not know the exact location. It was all buttoned back up by the time I saw it. GM doesn't seem to be documenting issues like this very well after they are resolved in the field. The GM Field Engineer who finally got involved on mine had seen something similar before and it was resolved the same day, yet the folks that my dealer had been working with had essentially said "Good luck, let us know what you find". If your dealer is unable to get the information needed to resolve it, have them contact Dave Cross Buick GMC in Lee's Summit, MO and ask for the service manager. He will be able to get them the info.

Finally after 51 days at the dealer, a GM Field Engineer figured out the issue. There is a harness near the firewall on the engine bay side that was rubbing causing the squeak. They had to drop the drive shaft to get to it.

I have this same squeaking with my AT4. 2,000 miles on it currently, but it has been doing it since around 300 miles. I agree that the squeak happens when the frame moves and appears to be coming from behind the climate controls, which is adjacent to the push button start. After one unsuccessful attempt to locate it by the dealer, I removed the majority of the console and center stack. Still could not pinpoint exactly where it was with the duct work in the way, but it was significantly louder. I am also guessing it at or close to the firewall. It is back at the dealer for round 2.