Shows the drive mechanism for the impeller. Top is nose cone assy ( upside down). Notice the 3 pins on each assy. There is what appears to be a 6 hole phenolic coupler ( no photo)that act as the coupling between them. The coupler has 3 of the holes reinforced which go to the Impeller side. I believe slight wear on these holes might be the cause of the clicking sound found in some of the units.
