For the benefit of the new transmission forum and the at least temporary loss of the ability to do a search on the old forums, I guess that I should go over this again.
The ATX on our cars does not have a media type filter, only a screen, so there is no need to pull the pan and change the filter when doing a trans service.
There is a drain plug on the ATX pan, so the fluid in the pan can be drained without removing the pan. This will only drain about 4 quarts of the 10 quarts in the system, since there is no drain on the torque converter. The Haynes manual recommends draining the trans pan, refilling, running the engine for a few minutes to pump things around (driving a mile or so also helps), then draining it again. This method is clean and easy and is probably satisfactory most of the time if the fluid is not badly damaged. Some do it a third time so as to more closely aproach a 100% fluid change. Since not all of the fluid is drained at any one time, you will never get a 100% change, even if you do it 10 times.
If you want a 100% change, you can do a flush using the hose in a bucket method. Find a 5 gallon plastic bucket. Calibrate the bucket in quarts so you can easily measure the fluid that you have drained out. Calibrate the bucket by using a quart container an adding water to the bucket one quart at a time. Mark the bucket with a Sharpe pen of with something that will make a perminate marking on the plastic. Dump the water and dry out the bucket. Remove the upper transmission cooler line at the radiator and attach a piece of hose to the line and extend the hose into the bucket. Remove the transmission dipstick and insert a transmission funnel. Start the engine. Add fresh fluid to the funnel at the same rate is the fluid is pumping into the bucket. It doesn't hurt to get slightly behind, but not by more that a quart or two. It will take 10 quarts to get a complete fluid change. If the fluid was very dirty, you should probably use 12 quarts or in an extreme case, 15 quarts. The fluid going into the bucket should be as pristine as the fluid going in to the funnel. When the fluid is clean, shut off the engine, reinstall the cooler line, start the engine to check for leaks where the cooler line had been disconnected, top off or adjust the fluid level, then road test. Check the fluid level again after the road test.
Naturally, you need to make sure that you do any of this in a safe manner. If you are not comfortable with any of this, you should probably not try it yourself.
