The problem is even normal driving can push fluid temperatures well beyond safe limits. But if the fluid temperature goes much higher, the life of the fluid begins to plummet. If fluid temperatures can be held to 175 degrees F., ATF will last almost indefinitely - say up to 100,000 miles. Normal driving will raise fluid temperatures to 175 degrees F., which is the usual temperature range at which most fluids are designed to operate. It doesn't take long for the automatic transmission fluid (ATF) to heat up once the vehicle is in motion.
Most owner's manuals have longer service intervals for automatic transmissions, but these intervals may be too long.Īn automatic transmission creates a lot of internal heat through friction: the friction of the fluid churning inside the torque converter, friction created when the clutch plates engage, and the normal friction created by gears and bearings carrying their loads. For optimum protection, You may want to change transmission fluid every 36,000 miles.
