Yamaha GRIZZLY ULTRAMATIC YFM660FP Owner's Manual page 318

5. Fill the differential gear case with oil.
Recommended oil:
SAE 80 API "GL-4" Hypoid gear oil
Oil quantity:
Periodic oil change:
0.28 L
Total amount:
0.33 L
CAUTION:
Be sure no foreign material enters the differen-
tial gear case.
6. Install the filler bolt and tighten it to the speci-
fied torque.
7. Check for oil leakage. If oil leakage is found,
check for the cause.
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