Automatic Transmission: Fluid Change Vs. Power Flush

by Richard Rowe

Transmission fluid is generally one of the most neglected fluids on any car. Though most people have a basic idea of why engine oil changes are important, very few seem to understand the benefits of a transmission fluid change and flush.


The purpose of a power flush is to completely replace all transmission fluid with fresh oil without allowing any of the original oil to linger in any of the transmission's many passages.

Standard Fluid Change

The standard practice for a transmission fluid change is to drain the transmission oil pan, refill it, run the engine and top off as needed.

Power Flushing

Power flushing a transmission involves connecting a pressurized line full of fluid to the filter mount and pumping new fluid into the running transmission while allowing the old oil to drain out.

Standard Change Advantages

A standard fluid change is usually much faster and less expensive. Standard transmission fluid changes use only around 5 to 7 quarts of fluid, as opposed to the 20 for a power flush.

Power Flush Advantages

Changing the fluid in the pan does nothing for the 5 or more quarts trapped in the torque converter. A power flush replaces all fluid everywhere in the transmission for greater longevity and increased performance.

About the Author

Richard Rowe has been writing professionally since 2007, specializing in automotive topics. He has worked as a tractor-trailer driver and mechanic, a rigger at a fire engine factory and as a race-car driver and builder. Rowe studied engineering, philosophy and American literature at Central Florida Community College.

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Photo Credits

  • photo_camera Image by, courtesy of Brittany Culver