Most automobile manufacturers recommend that you change your transmission fluid every 3years/36,000 miles (consult your owner’s manual). We recommend an annual fluid change. If your vehicle is older, or is used for towing, it may be required more frequently. To determine if a fluid change is needed, we recommend our External Diagnostic Service– which includes checking the level and condition of your transmission fluid, a road test, and putting your car on a lift to check your external transmission controls– to keep your transmission, and your vehicle, running smoothly.