Gear Differential Set 39T (For HB-TCX & TCXX)

The Gear Diff consists of light weight plastic housing; nylon gears and long life diff joints. It weights at 26g and optional Aluminum Joints are available to reduce weight further. Long lasting and durable material result in consistent and better performance. Gear Diff setting tuned by oil weight stays consistent throughout the race and it does not require frequent re-builds like a ball diff.

Built-Up Tips

• Assemble the entire Differential unit


• Rotate the Differential from each side to make sure the internal gears operate smoothly


• Diff feels coarse when the internal gears are too tight. Open the Diff and use fine sand paper to sand the flat side of the large internal gears, re-assemble and test again. Fill the Diff with diff lube when Diff feels smooth.


• Diff feels very loose when the internal gears are loosely meshed, add a 0.1mm shim on the bottom of the larger internal gear, re-assemble and test again. If the diff operation is still loose add another 0.1mm shim to the bottom of the opposite large internal gear. Diff should feel moderately smooth but not too loose or too tight. Fill the Diff with diff lube when ready.


• Fill the Diff to about 1/2 of 2/3 full. Do not over or under fill the Diff.