GPM Racing Steel 9T Pinion Gear for Traxxas 1/10 TRX4 (TRX4009T)

Technical 9T Pinion for TRX4 Drivetrain Upgrades

The TRX4009T is a hardened steel #45 9 tooth motor pinion intended as an aftermarket replacement for TRAXXAS TRX4 crawler drivetrains. It is engineered to handle low speed, high torque conditions typical of serious crawling setups.

This pinion is specified to fit motors with a 3.175mm centre bore and to mate with 32 pitch spur gears, yielding roughly 0.8mm tooth spacing. It mounts to the motor shaft and transmits torque into the transmission train where a 9T ratio is required to prioritise torque at the wheels.

Install by securing the pinion with the supplied 3*3 screw shaft and set the gear mesh carefully to avoid axial or face loading. Inspect bearings and spur runout when upgrading to hardened steel components to ensure reliable long term durability under crawl loads.

Packing includes

• 3*3 Screw Shaft – 1pcs

This item is compatible with

• TRAXXAS TRX4 Defender Trail Crawler

What material and hardness is used?

The pinion is manufactured from hardened steel #45 to provide improved wear resistance for low speed, high torque crawler use.

What tolerances should I check during fitment?

Verify motor shaft concentricity, spur face runout and axial play. Proper mesh and bearing condition reduce the risk of premature tooth wear under load.

Recommended maintenance for longevity?

Regularly inspect gear teeth and bearings, maintain correct mesh, and replace the pinion if any signs of pitting or excessive wear are present to preserve drivetrain reliability. Write Product Review Please sign in your account before you can write any review. Sign In Close

Made to order: GPM Racing parts are shipped to us from GPM’s factory, so please allow around 14 days for dispatch.