Just dropped mine off at dealer this morning after 10 days and 900 miles. Per what's happened with most of you, they are checking tires for balance and/or flat spots. Have had 2 loaners (Z71 4WD and LT 2WD; both dbl cabs) within the 10 days (first minor issue not vibration related) and both have had a smooth ride compared to my LTZ. 500 highway miles this past weekend and it felt like I was sitting in a vibrating massage chair; not a feature I saw on the window sticker.......? Maybe I'll be one of the lucky owners and be able to move on to more positive topics. Will update with results when I go back to check the results
Hmmmm .... Just noticed the current loaner has Continental tires instead of Good Year like mine....