I feel for you guys. I had mine for 3 months...3 of the longest months of my life. I was just never happy with the truck. I had the vibrations (1500 CC Z71) and the dealership where I bought it (and 3 other GM vehicles the past 5 years) stopped troubleshooting after swapping out rims and tires, and told me I needed to wait for a TSB.
I could have pushed the issue, but I wasn't upside down and decided to cut my ties with GM and bought a 2014 Tundra, which I am very happy with thus far.
Good luck fellas...I hope GM steps up and helps you guys out.