What should you do with a stuck motor?

Last night I had a new-style 9V motor attached directly to a 40-tooth gear that
was turning an 8-tooth gear. There was a fair amount of torque involved, and my
motor stalled after a while. Now the thing won't turn unless I really force it.
What should I do? Should I call LEGO and have them send me a new one? Should I
take it apart and try to fix it? What happened to it, anyway?

The motor in question is from a Mindstorms 2.0 kit, and the number on the bottom
is 43362.