On the 2003 trans filter, it looks like there is a hole in the top? Unlike an oil filter, what is insertrd in the hole to keep the fluid from coming out. Told you it was a dumb question, but I'm serious!
If you go to the meet your trans filter thread there is a diagram that shows a hose covering that opening. I just recently changed mine it was a pain to do but it's not super difficult.
what do you use as a jacking point btw? not really related. I was looking for the filter underneath before I realized it was behind the battery. I placed the jack under the transmission pan near the drain plug. bad idea?