[Gary Dillard]

Years ago they supplied the whole window drive assembly in the kit; this motor attaches to a hard plastic coupling that drives a flexible plastic tape through a track. It doesn't have much horsepower so I wouldn't worry about bending stresses or contact stresses with a metal gear. You can turn down the teeth; you're changing the tooth profile but it wouldn't match this gear anyway. One suggestion - if you use a brass gear, the brass will "self-work" to the appropriate profile somewhat (we've used this method meshing to the small pinions on the other motors in our drive trains for years).