Personally I am against flushing unless you have done it on a regular basis since new, but even then it seems totally unneeded to me. You could just pull the lines to the cooler and let one pump old fluid out while the return sucks in clean fluid, if that was Gadget's method I apologize, I did not read it.
I bought my 02 at 54k and the dealership had just drained and filled the tranny, so I am continuing that practice. I am at 102k now and have drained the fluid 3 times since buying and dropped the pan twice, putting in a new filter the second time. The filter is just a metal case with a metal screen and can be cleaned and reused a time or two. If you do choose to drop the pan a few things to keep in mind, you will need to lower the front sway bar to get the pan out. The dipstick will come apart about half way down, it is held together by a rubber grommet, so just spin and twist until it comes free, but after removing the 12mm bolt that holds it to the block. They sell kits at auto parts stores with a new filter and a gasket, the rubber gaskets are best. Toyota uses RTV, which I did the first time, but you have to scrape all the old stuff off each time, so to me the rubber gasket is easier. When putting the pan back up don't overtighten the many screws, they go into aluminum and will easily strip. Make sure after you fill it up you drive it until nice and hot and then check the level again. I use the Toyota D3 fluid, but if you do choose a flush you may want to switch to synthetic and then just run it longer. Knowing the history of these trannies I like the idea of changing it often so I can check the condition, so far mine has always looked brand new.
