2002 Yamaha YFM660 Grizzly factory service and repair manual, Page 127Get this manual
CHANGING THE DIFFERENTIAL GEAR OIL
CHANGING THE DIFFERENTIAL GEAR OIL 1.Place the machine on level surface2.Place receptacle under the differential gear case3.Remove: Oil filler bolt Drain plug 4.Drain: Differential gear oil 5.Install: Drain plug 10 Nm (1.0 kg, 7.2 ft lb) NOTE: Check the gasket (drain plug)If it is damaged, replace it with new oneT