Alan,
If it were me, I'd check to make sure the gear is rotating in the way described in the datasheet (I think it's so the flat part on the top is pointing away from the middle of the gear. Check the datasheet to be sure.) I hooked up our hall-effect to a proto-board and it wouldn't do anything until the gear was positioned correctly. By the way, I will test some more, but I couldn't get much of a duty cycle change out of the hall effect sensor by changing directions. I may do more testing on this, but as of now, it's software's problem

Keep us updated.
Sparks