RC Differential Tuning Oil #7500 - Yokomo RP-085075A  [RP-085075A]

Silicone oil tuned for differential control

The Yokomo RP-085075A Racing Performer Ultra diff oil #7500 is a silicone lubricant formulated for use in radio-controlled gear-type differentials, intended to preserve consistent damping and limit internal friction under continuous load. The #7500 label denotes a specific viscosity choice to influence slip and lock behavior without modifying gear geometry.

In practical tuning terms, heavier diff oils increase internal resistance and produce a more locked response under acceleration and on corner exit, while lighter oils let the driven wheels turn more independently. The RP-085075A #7500 offers a high-viscosity alternative for rigs that need a firmer centre lock feel or reduced differential spin in slippery conditions.

Installation summary: remove the diff housing, drain existing fluid, check gears and bearings for wear or debris, then refill with an accurately measured volume of diff oil appropriate to your differential type and tuning approach. Cycle the mechanism after filling to remove trapped air and ensure smooth operation before reinstalling the assembly.

Care notes: refresh diff oil at intervals matched to running time and inspection, and do not mix different silicone oil formulas inside a single diff unless you have verified they are compatible, as additive packages and base fluids can alter results.