What you show in your video is a stripped gear in the mechanism. The motor doesn't have a stop, it shuts down when resistance builds up and that shuts down the motor. With a stripped gear, the motor isn't detecting the resistance and keeps running.
Unfortunately you can't just replace the gear, the motor and mechanism are sold as a unit. Fortunately, if you remove the motor/gears, you'll discover that they are identical to an inexpensive electric window mechanism available at any auto parts store. You could pay twice as much or more and order it from Kwikee, but the local source is just as good.
Be sure to disconnect power before working on it, the motor is strong and could bite or pinch you.
This manual may help you: