2002 Yamaha YFM660 Grizzly factory service and repair manual, Page 271Get this manual
FRONT CONSTANT VELOCITY JOINTS AND DIFFERENTIAL GEAR
Installation steps: Slide the shift fork sliding gear 1, which is installed to the differential gear, to the left to put it into the 2WD modeConnect two size batteries to the gear motor terminal to operate the pinion gear 3, and operate it until the paint mark on the gear is aligned with the paint mark on the gear motor case
CAUTION:
Do not use 12 battery to operate the pinion gear Insert
8 mm bolts into the gear motor and use them as guide to set the motor on the differential gear assembly so that the shift fork sliding gear does not move