I heard you have to drain out all of the fluid, fill it up and run it for a few miles. Then you repeat this step 3 times. It is what the manual says. It seems like a big wastes of ATF because ATF last 120k miles but for this flush process, it last 2 miles. I would probably save the new flush fluid and use it as engine oil for about 5k miles. It is also oil, just much thinner. Then again, I don't want to cheap out on a few bucks and loose a good engine.

I am not sure if the dealer really do the 3 flush thing or just charge you for the work and not do it. I know that they do not top off all fluid on the last 2 of my preventive maintenace visits. The coolant level was at Min and it stayed at Min after both visit, 7500 miles apart. I just poured some water in it and top it off myself. It is only 1/3 of a quart between Min and Max lines and that's a reserve tank, so I didn't want to buy a 1 gallon bottle for just that. I wont need that stuffs until 102k miles from now anyway.