From the factory, the differentials are filled with 30K weight silicone diff fluid. This is a little heavy for racing applications. As with any setup parameter, a balance is needed. For best results, it's good to lighten up the diff fluid to improve control in rough track situations and to make chassis rotation much easier in the corners. Generally, lighter diff fluid improves steering and rotation while heavier fluids allow more power to be transmitted to the tires without excessive unloading of the wheels, also known as diffing out.
The center differential (#5914) is a great option for improved traction under acceleration and through the rough. The center diff requires the installation of the rear brake kit (#5417). This allows you to adjust brake bias independently front to rear.Direct drop-in for the Slayer. Transfers power to the front and rear differentials independently. Sealed center differential is adjustable using various oil viscosities. Fully assembled with 100K oil.