I have used both Maya and Softimage to rebuild each pieces according to my proxy from zbrush. I have a hard time getting clean and straight line from zbrush. I knew there are methods from zbrush to do hard surface but I still think subdivide from a low res is still cleaner.
Although it is a very long process. Modeling/sculpting while designing is painful. This is the only method I know so far (completely un-production friendly)
I've gone thru a few other versions of each shape of the gear. Some parts are unsure until I made it to the final. Endup needed to be redo. I wish I can draw better so I 'd figure all that out in my concept.