Remove the window regulator from the door amd leave it inside. The window get turned 90 degrees and dropped in from the outside of the truck. Takes some wiggling and easier with 2 people. Once you get it in position you slide it up and then slip the regulator on . While its apart grease the regulator and track.
Windows without the metal all the way around the glass are alittle easier. Not sure if that started in 41 or 42