We have a 2006 Chevy Express 1500 with the sliding door w/o a window. We want to put in a window. The indentation in the sides of the van seems less deep than the indentations in the back doors. Since they seem to just sort of clip in and then, what? butyl tape, is it actually possible to install an OEM sliding door window into a door that never had one?

 

No. The window would break because there is no support structure.