I did the job last Friday and everything went fine. First I drove up on ramps and drained out the transmission fluid then reinstalled the drain plug. Then I took out the 18 screws holding it up and used a paint scraper to carefully
pry the corners to break the gasket seal. (Be very careful because it's easy to put indentions in the transmission case.) While I held up the pan, my friend removed the screw holding the dipstick tube bracket. There was still some fluid in the AT pan so I drained it after removing the pan from under my truck. I then removed the AT filter which unexpectedly
poured out fluid some leftover fluid on us.
The filter wasn't clogged and there were no visible holes, so I used a rag to clean off the outside and sprayed some brake fluid to wash out the inside. (I recommend WearEver BF at Advanced Auto Parts - stuff works great!) Toyota used RTV sealant to make the original gasket so we had to carefully scrape it off the pan and AT case. (I didn't have any gasket remover unfortunately.) Then I cleaned out the inside of the pan with brake fluid to get it spotless before reinstalling it with a rubber gasket from Advanced.
I was worried about metal shavings in the pan since I had read the drain plug didn't have a magnet on it, but I was pleasantly surprised that there are 3 magnets on the bottom of the pan
! They are spread out to catch everything - you can see wear they are located if you look at the square indentions on the bottom off the pan.
All in all it was a pretty painless job and I measured a little over 6qts that I drained out.