2005 Kawasaki KAF400 Mule 600 and Mule 610 4x4 Service Manual, Page 191Get this manual
9-22 TRANSMISSION Transmission Case
the Install[B] following parts on the drive shaft [A]Pin
Install the governor drive gear so that the flat side [D]
faces to the circlip
Governor Drive Gear [C]
Install: [A] Circlip