Yep, I'd say that's the Intermediate Steering Shaft. These GM trucks and SUV's seem to have had problems with that part ever since they were redesigned--and at this point, GM has gone through several different revisions of the part itself.mikeee said:
Take it into the dealer and explain what's happening, and mention the Intermediate Steering Shaft. Most likely, they'll already know full well about it and just replace it anyway--most keep the part in stock since it's such a common problem.
Couple years ago, GM just told them to keep re-lubing the shafts when owners brought them in for the problem, but they soon realized that was no more than a temporary fix. When we had our '02 Avalanche 2wd, my mother noticed that there was a "rattle and clunk" when she turned a lot of the time, especially if turning and hitting a bump at the same time. Back then, the dealer just lubed it and it stayed good. Had the same problem with our '04 Suburban, only worse (said she really felt it clunking and rattling when turning and going over a bump), called the dealer, and they just immediately replaced it with the latest part # one.