Ok heres what happend. My dad got a 2011 silverado and wantes to put some of those nerf bar step tubes on it. When he went to install them he took the impact gun to the bolts for the body mounts and the first came out but the middle and last one are just spinning. I guess there is some sort of clip nut or something up in the cab mount that has broken loose and is now turning. Has anyone ever run into this? Any idea's on how to fix? Thanks