2002 Yamaha YFM660 Grizzly factory service and repair manual, Page 126Get this manual
CHANGING THE FINAL GEAR OIL CHECKING THE DIFFERENTIAL GEAR OIL 6.Fill: Final gear case
Periodic oil change: 0.28 (0.25 Imp qt, 0.30 US qt) Total amount: 0.33 (0.29 Imp qt, 0.35 US qt) Recommended oil: SAE 80 API "GL-4" Hypoid gear oil
CAUTION:
Take care not to allow foreign material to enter the final gear case7.Install: Oil filler bolt