Automatic transmission service entails removing the transmission fluid pan, discarding the old fluid and replacing it with new. An automatic transmission flush, on the other hand, pushes all of the transmission fluid out of the fluid pan, body and torque converter, allowing a cleaner and more efficient replacement of fluid.
An average transmission flush is a total fluid replacement in all connecting parts of the transmission. Using a pressurized filtered fluid machine, the operator forces all of the old fluid out. After completing the flush, the machine pushes a cleaning agent through the system to clean all internal parts of the transmission. Because of the flush machine's pressure, the operator will find any unseen internal problems the transmission my have.
One of the benefits of a flush is it expels and replaces all fluids, removing any chunks, buildups or debris from the transmission. An entirely new 12 quarts of transmission fluid (the average amount of fluid a car holds) will allow a healthy transmission to function more efficiently. In addition, a fluid flush might help indicate any internal problems not usually detected by a regular transmission service. The pressurized nature of the flush can dislodge chunks or buildup in the transmission, valve or tubing. A pressurized fluid flush can also find otherwise undetectable micro fractures or leaks that would be detrimental over time.
Sometimes, flushing a transmission will dislodge debris from the valve body but not fully push it out. This can actually end up causing transmission failure. Flushing can blow out transmission seals causing damage to the transmission if there is too much pressure. A regular service can indicate internal transmission problems because of the need to remove the pan. A person may notice excessive metal debris in the fluid pan that would not be as evident with a full flush of all transmission fluid. Owners can easily change transmission fluid themselves on most cars, but a pressurized generally requires a mechanic.
