Sprayed vehicle including under body weekly, and more during winter, with a cab forward frame perfect condition. The rear of cab back, including bumper, is rusted completely through. Replaced 3 frame crossbeams, the shock mounts, bumper & mounts, rocker panels, rear cab mounts, tank straps/mounts and bed rails under bed. Just found this site. I replaced the 2015-2016 at 120,000 miles. There's 140,000 current miles.