I am running higher torque motors. I have 381 oz. steppers. I have my doubts that it was due to that though. I have re-packed the ball nuts a couple times and came the conclusions that the 'catch' that is supposed to keep the balls from getting past the recirculating tube broke off. I don't see a way to fix it either. This 'catch' appears to be a little piece of the recirculating tube that they intentionally leave sticking up in the nut. So I can re-pack the nut, wind it back onto the screw but as soon as I reverse direction, all the balls spill out the other side.

I have been hunting for a replacement but I have yet to find anything I can make fit without getting into significantly modifying the table.