A is vertical drive shaft from above for Slew... B is pinion on centre shaft driven by A... C is a gear being used as a spacer. I've run out of collars... D & E are reduction gears... F drives inside of gear ring... G was supposed to drive the gear ring as well to share the load with F, but everything was binding, there was no backlash, so I turned it over and it is now just a spacer.... Pinion under gear ring and at top of centre shaft are just spacers....