Most manufacturers suggest servicing your transmission every 25,000 miles. (Check your owner's manual for specific service intervals.) The transmission works with the engine to provide power to your car's wheels. It keeps the engine’s output optimally matched to the speed and load conditions. Transmission ﬂuid serves a multitude of purposes. It cleans, cools, lubricates, transmits force, transmits pressure, inhibits varnish buildup and continually protects the transmission. Changing your transmission fluid is like changing your motor oil. The fluid wears out and needs to be changed to prevent the breakdown of your transmission. lt’s recommended to replace the filter and gasket when having your transmission serviced.