Disclaimer: Consult your Yamaha dealer concerning warranty issues before performing this modification.

Keeping your fluids changed regularly is critical for longevity and reliability.  In addition to engine oil, your differential and final drive oil must also be changed on a regular schedule.  Before proceeding you should be aware of the difference in the differential and the final drive.  The differential is the front ring and pinion housing.  There is no differentiation in the spooled rear so the rear ring and pinion housing is referenced as the final drive.

Required Parts & Tools:

• 12mm wrench
• 14mm wrench
• 5mm hex wrench
• 10mm socket
• 21mm wrench
• 1 quart Valvoline 80w 90
• Drain pan
• Funnel with hose

While removing the skid plate(s) isn't necessary to change the fluids, it makes access a little easier.  Use a 10mm socket and remove the mounting bolts.

Just above the rear receiver hitch is the fill plug.  Remove this plug with a 14mm wrench.

The final drive drain plug is located near the bottom of the final drive case.  Place your oil pan underneath the differential and remove the drain plug with a 12mm wrench.  Allow this to drain until the dripping stops.  To save time, while the final drive oil is draining you can skip ahead to the differential and start removing the front skid if you plan to.  Once the oil has stopped draining you replace the drain plug.

Fill the final drive housing with oil.  Keep filling until it starts to weep out of the fill hole, then replace the fill plug.  Check everything for leaks and then replace your rear skid plate.  You're now finished with the final drive oil change and can proceed to the differential.

The differential fill plug is difficult to reach without removing at least the front 6 bolts of the skid plate.  Remove the differential fill plug using a 21mm socket.

The differential drain plug uses a 5mm hex wrench.  With your drain pan underneath, remove the drain plug and drain all the oil.  Once the differential is completely drained, replace the drain plug.  Beware: its very easy to strip the drain plug housing threads.

The differential fill hole is much more difficult to access than the final drive fill hole was.  Insert the funnel hose into the hole and route the funnel behind the front bumper.  Fill the differential with oil until it runs out the fill hole, and replace the fill plug.  Check for leaks and replace your skid plate bolts.

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