I just had to replace a front door on my Aerostar. The junkyard door I picked up would not move the window all the way. When going down sometimes the window would hang up, and twist slightly, jamming it in the tracks.
I sprayed the tracks with a silicone spray lubricant, and that helped a little. I then reached inside the door, and pulled the front track aft, and the rear track forward, and removed the extra space that allowed the window to twist.
I also put a little bit of fresh grease on the window regulator, and even took the motor apart, and worked some new fresh grease into the gears of the motor.