When Should the Transmission Fluid in an Automatic Transmission Be Replaced?

[MorganRose]

The transmission fluid in an automatic transmission should be replaced every two years or every 40,000 kilometers. Transmission fluid deteriorates and evaporates under prolonged high-speed and high-temperature conditions, which can accelerate the wear of mechanical components and, in severe cases, damage internal transmission parts. If the transmission fluid is not replaced for an extended period, the vehicle may experience symptoms such as weak acceleration when starting cold and slight slipping during driving. It is important to note that automatic transmission fluid cannot be completely drained using atmospheric pressure alone, as this method only removes about half of the used fluid. The remaining fluid, along with sludge and impurities, can accumulate in the valve body, torque converter, and cooling lines, leading to blockages in the internal fluid passages of the system.