We recently bought a well used and abused 2008 Tundra and the tailgate had been overloaded, bent, and sagging. It was bowed so much it hit the bumper and tried to lift itself off the hinges when opened. The lower inside of the shell was beaten down. I had nothing to lose, so I went about bringing it back to life. I welded a chunk of angle iron to the inside and levered it up with some hardware, a pipe, and a jack.
More to come.