How often should I change my automatic transmission fluid?
Some automatic transmissions in 2002 and newer vehicles have “100,000 mile fluid”. The perception is that you don’t need to change the fluid for 100,000 miles. This all depends on the type of driving you do. The “100,000 mile” fluid is based on normal transmission operating temperatures of 175 F and not pulling a trailer or heavy load. Maintaining this type of fluid is no different than maintaining the old style of fluid. Let’s talk about driving styles. For example you can drive up I-5 or I-405 on any given summer weekend and see how many vehicles are towing a trailer or heavy load and driving on the shoulder because the trailer or load is so heavy. You may even be one of these drivers. This type of driving increases the normal operating temperatures inside the transmission and then the oxidation rate doubles with each 20 degrees increase in transmission operating temperature. The useful life of the fluid is now cut in half. At 235 degrees the life expectancy is only 12,000 miles. At
