I arranged to take a service technician for a test ride before I left my truck just to make sure they heard the noise. This is the moaning/rubbing noise that comes up when turning left. As soon as he heard it he knew what it was... steering gear.

He said it's very common problem in Tahoes and Suburbans. He's seen a few in the diesels but not many. Also, I ask him about the redesigned steering shaft. He said they are getting a bunch of those back with the same rattling noise. Hopefully mine will last.

John