Brinn Transmissions RT1 racing transmission fluid is a multi-viscosity fluid which protects the unique wet clutch systems used in Brinn transmissions. Not only does RT1 protect your clutch but all of the critical bearings, shafts, and gears. Lesser quality fluids can cause oxidation due to heat from the abuse of hard racing conditions. RT1 is recommended for all Brinn transmissions and the only suggested fluid for Brinn’s Predator transmission.