2001 Mitsubishi Eclipse trying

In an auto trans, most of them are at the bottom of the trans. Take off the pan and its what you see.

I've never taken off a MITS trans filter, but you can bet its accessible and inside whatever panel come off. Jack it up (use jack stands please), crawl under your car and you'll see a bottom panel.

Get a large pan, it always turns into a mess.
The trick on changing your fluid and filter is getting the fluid out of the torque converter.