Finally I got back to my new Shopbot assembly and finished the wiring today. I have the expected X and Z movement but no Y. With the motor disengaged from the gearing I get smooth easy movement. With the gear engaged and motor disconnected from the driver I get harder but still smooth movement. When I use the keypad to move the Y and hold the Y motor I can feel one very slight 'clunk' when moving away from 0, when trying to move back toward 0 I feel nothing. So, should my next step be to unplug the X motors and plug the Y motor in one of the X drivers to see it that helps? And if it doesn't, what then?