What is the recommended millage for a transmission flush

Transmission fluid should be changed every 30,000 miles, or more frequently if the vehicle is used for towing or carrying heavy loads.

When replacing the transmission fluid, first the mechanic drives the vehicle to get the fluid warm and then removes the drain plug at the bottom of the transmission (if applicable), or removes the transmission pan allowing the fluid to drain.

The transmission is then filled with fresh fluid, and the engine is started. With the engine running and the transmission in "Park," the mechanic checks the level of the transmission fluid on the dipstick. Then the vehicle is driven once more, and the fluid level rechecked; if needed, more fluid is added.

Using the wrong automatic transmission fluid may invalidate the manufacturer's warranty and affect the shift characteristics of the transmission. Consult the owner's manual for information on the kind of fluid to use.

Many automatic transmissions have a filter that can be replaced when changing the transmission fluid. Changing this filter may allow a closer examination of the fluid for debris, which may be a sign that the transmission is about to fail.

Hope this helps.