Went to install mud flaps on the rear and the back portion of the box is not stable, I can wingle both sides pretty good. Checked to see if something was loose or broken, did not see anything. I looked on gm,s parts site and did not see anything. Anybody have this problem?

 

Found the problem, went to GM dealer and had the body shop look at it and they found that both box sides were replaced and who ever did it did not do it right as the inner panel should be either welded or some type of glue. So I have an appointment with the selling dealer to find a solution.

 

the dealer stepped up and fixed my truck, I am so happy right now.