When I go to roll down the back window the motor will turn but the window does not move. I can move the window up and down by hand, but it doesn't fall like a window that is off track normally would. I have to push or pull pretty hard to get it to move. I haven't gotten a chance to check it out internally, but just wanted to see if anyone else has had the same problem or get an idea of what I need to be looking for.

 

Ford uses the same motor in all the doors in all these trucks and tons of cars from the same era and they all develop the same problem. Inside the gearbox there are 3 composite rollers that disintegrate over time, they aren't expensive or difficult to replace... once you get the motor out of the door. Ford Motor Rebuild Kit

 

Thanks. That is exactly what I was looking for.