The motor is probably just fine. What goes bad on Ford power windows is 3 little hard rubber pieces that act as shock absorbers and connect the motor drive to the gear that operates the window. Unfortunately, you can't buy just the 3 little rubber parts (imagine that!), you have to buy a gear kit which includes the plastic gear that engages the motor, the 3 rubber parts, and the metal gear that engages the window lift. You can get the kit at some autoparts stores for around $30 if I remember correctly. Make sure you take your motor apart first (see instructions in the post above) and take the gears with you because Ford changed the size of the gears sometime in the late 80's or early 90's. When you replace the gears, make sure you get every little piece of the old rubber parts out of the motor housing or you'll have problems.