My toter had the same problem with the motor that moved the slide-out in and out. Of course it stuck IN KANSAS with the slide-out in the OUT position. Talk about scared. But I whapped it a few times and it cranked it on in. There is a manual crank on those things, but boy, it looked like it would have been a huge bitch to get that done by hand. The motor went on in, but still didn't act quite right. I called my dealer when I got back who then got in touch with the manufacturer. Strangely they said that they've sold hundreds of those and NEVER had a problem with one of those motors. They didn't seem to want to fix this one, either, since it went to working. I demanded that they replace it under warranty, though, as I didn't want to get stuck with it out. I honestly think to move it by hand would be 30-45 minutes of hard cranking (that slide-out was 12' long and probably weighed a couple thousand pounds!). They did, and I never had any more trouble.
Anyway, often times those DC motors will just get crud stuck in between the brushes and armature and the rapping will knock it out and they're fine. But if it starts to happen again quickly, you have something a little more serious going on, unfortunately. If you see any little screw-like plugs for the brushes, it won't hurt to open them and pull the brushes out and inspect them. Post pics!
--Donnie