While you're in the door checking things out be sure that the rubber window bumper is installed. Over the years this chunk of rubber will dry rot and crumble, eventually falling out of the retaining bracket. When this happens the window can be rolled down past the door's beltline, causing the glass to sometimes jam when rolling it back up. Also check the condition of all window rollers, and door lock rod retainers too while you're in the door. Scott Drake (Drake Automotive Group) makes a nice selection of replacement door parts perfect for this project.