How Often Should You Change Transmission Fluid in a Racing Automatic Transmission? Automatic transmission fluid (ATF) comes in a wide variety of types and specifications. For your daily driver, fluid changes are required very seldomly in most cars and trucks and should be filled with the manufacturer’s recommended fluids. In a racing automatic transmission, fluid usage and recommendations vary wildly depending on the transmission builder’s preferences, experience, car weight, engine type, and racing conditions. For most racers, a synthetic or semi-synthetic is the best choice. Fluids such as our BTERead More