A transmission flush is a procedure to remove old automatic transmission fluid (ATF), sludge, and grime from a vehicles transmission and replace it with fresh fluid. The purpose of ATF is to cool and lubricate your automatic transmission. Over time, transmission fluid collects foreign particles that can interfere with these functions, causing your transmission to generate more friction and heat. Eventually, these particles can build up into sludge deposits in your transmission and interfere with shifting and acceleration.

Here are some key points to know about transmission flushes:

• A transmission flush is different from a transmission fluid change. A fluid change replaces 50%-60% of your transmission fluid, while a flush replaces 100% of it and purges accumulated particles and deposits from the entire transmission.
• A transmission flush helps maximize the lifespan and performance of your automatic transmission, but it does not help with preexisting transmission problems.
• Regular transmission flushes can increase the lifespan of your transmission and improve your driving experience.
• A transmission flush is more expensive than a fluid change, and some people warn against performing a flush on a transmission using old, dirty fluid.
• A typical flushing machine uses hoses that connect into the transmission cooling lines. It drains the old fluid and holds it inside the machine while replenishing the transmission with new fluid.
• The cost of a transmission flush can vary depending on factors such as the year, make, and model of your vehicle.

In summary, a transmission flush is a procedure to remove old automatic transmission fluid and replace it with fresh fluid to maximize the lifespan and performance of your automatic transmission. It is different from a transmission fluid change and can be more expensive. Regular transmission flushes can help prevent transmission issues and improve your driving experience.