Well i am sad to say I have to add my name to this list.
Just purchased a new 2015 double cab LT 5.3 2wd. I have owned several GM trucks and bought this one without a test drive.(stupid me)
2200 miles, 2 dealers, and 3 dealer visits already and still 75mph shake. The selling dealer is incompetent and has dropped the ball several times and is not taking my situation serious enough for me. I am contacting GM customer service to hopeful get someone to take this issue as a priority for me. So unhappy with new purchase because of this situation, and I love GM truck and want to give them the benefit of the doubt.