The pinion nut on the Honda TRX-300 4x4 is the main component that holds the proper torque on the rear differential bearing. The nut is made up of left-handed threads instead of the common right-handed threads. Use a hammer and a chisel to remove the pinion nut from the threads of the pinion shaft. Reseat the nut with a ratchet, socket and then a torque wrench to set the bearing properly inside the differential.
Spread a generous amount of multipurpose grease around the threads in front of the pinion nut.
Place the flat tip of a chisel on one of the top corners of the pinion nut. Angle the other end of the chisel out toward you.
Strike the end of the chisel with a hand-held sledge hammer in a right-hand direction. The pinion nut has left-handed threads, so it will have to turn in a right-hand direction to loosen from the pinion shaft. Continue hitting the chisel against the top corner of the nut until the nut loosens.
Move the flat tip of the chisel to the other top corner of the pinion nut. Strike the chisel with the hammer to loosen the nut more. Continue striking and moving the chisel across the top of the nut until the nut is completely loose from the threads of the pinion shaft.
Remove the nut from the pinion shaft and inspect the threads of the shaft for any damage. To reinstall the pinion nut, clean the threads of the pinion shaft and screw the nut onto the shaft in a left-hand direction. Tighten and torque the nut down to the proper torque settings.
