This summer we put 3500 miles on our 70 A/S and towed it with out 04 Suburban. Our 70 is a one owner and in fine shape. While backing into a slot one afternoon, I left the rear hatch open on the Surburban, it is a one piece flip up door. As I took a small corner, I heard a crack sound. The corner of the rear door had connected with our black plexiglass window protector on the front window, put a nice little hole in it.
Sooo, do not leave your rear door open on Chevrolet Suburban when backing up or going forward.