Honda TRX450R Transmission Fluid

How to Replace the Transmission Fluid in a TRX450R

Honda recommends replacing the transmission fluid every 100 hours, 600 miles, or 12 months (whichever comes first). Under race or severe conditions, it doesn't hurt to keep the fluid changed more frequently - doing so will maintain shift quality and clutch feel while affirming an additional layer of protection against wear.

Transmission Fluid Change Interval: 100 hours, 600 miles, or 12 months
Transmission Drain Plug: 12 mm
Transmission Check Plug: 10 mm
Fluid Viscosity: 10W-40, 5W-30
Transmission Fluid Capacity: 0.58 quarts (2004-2005), 0.72 quarts (2006-2014)


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Amsoil Dirt Bike synthetic oil

We're using Amsoil's full synthetic "Dirt Bike" 10W-40 oil. We can attest to the quality of the engine/transmission oil and its favorable characteristics when used in the TRX450R, which include a significantly improved, highly comfortable clutch feel and engagement properties. To learn more about this product, we recommend visiting: Amsoil Synthetic Dirt Bike Oil

Transmission drain plug location

• Start and run the engine for 2 to 3 minutes, then shut down and allow to cool for 3 to 5 minutes.

• Locate the transmission drain plug and position an oil drain/catch can beneath it. For 2004 and 2005 model years, the transmission drain bolt is located beneath the rear brake pedal on the right hand side of the ATV.

2006+ model year transmission drain plug location

• For 2006 - 2014 model years the transmission drain bolt is located beneath the shifter on the left hand side of the ATV.

Draining transmission oil

• Using a 12 mm socket and extension as necessary, remove the transmission drain bolt. Once the transmission fluid has drained completely, apply a light coating of fresh oil to the bolt and replace it; torque to 16 lb-ft, do not overtighten.

Transmission fill plug location

• Locate and remove the transmission fill level bolt (refer to arrow in fullsize image) with a 10 mm socket. The fill level bolt is located just to the left of the timing hole cover on the right hand side of the engine. There is a small arrow cast just below this bolt pointing upwards.

Refilling transmission with new oil

• Remove the transmission oil fill cap and slowly add fluid until it begins to weep out of the transmission fill level hole.

• For reference, 2004 and 2005 model years require 0.58 quarts of fluid while 2006 to 2014 models are spec'd for 0.72 quarts. Once the transmission has been filled to capacity, replace the fill level bolt and transmission fill cap.