In addition to broken teeth on one of the drive gears, the gears are connected to the drive shaft by rolled pins. I have had one of the pins work its way out of the hole on a couple of occasions, and the pin sheared off once.
An even more common cause of the slide out of alignment is one of the bolts between one of the drive shafts and the motor has sheared. You can temporarily use a 1/4-20 Grade 8 bolt as a replacement, but the Power Gear slide mechanism uses a special Grade 8 bolt and nut as shown below. Tiffin has the correct bolt and nuts. If replacing a drive bolt, it is also important to tighten to the recommended torque.
If the drive motor will still run, have someone push the button to extend the one end of the slide while you push out the other end manually. I sat down on the floor and braced my back against the fridge while I pushed the slide out with my feet. Jog the button as necessary to keep the slide as straight as possible. Once the slide is out far enough, you can climb underneath and turn the square shaft on the end where broken bolt is located with a big Crescent wrench to fine tune the position of that end of the slide.
If the motor won't run, the slide may have bound up enough to overload the motor and blow the fuse. I not sure where that fuse is located, but there are more 12V fuses and 12V breakers in the bay behind the right front wheel in addition to the fuse/breaker panel inside the coach.
Let us know what you find.