There is an o-ring that secures and seals the tube to the hole in the trans housing. The tube is secured to the top side bolt of the trans via a small flange.
What I did when I swapped my trans, drain as much trans fluid out of the pan (sucking through dipstick and using gravity to drain - get clear tubing some 6' long, remove dipstick, put into fill tube till it bottoms, crawl underneath making sure clear tube hangs below trans level....start sucking till you see trans fluid coming down the clear tube, put clear tube into container to catch fluid). Once trans is empty, put hood against windshield, crawl on top of engine, wrap small rope like an 'X' around flange, rest head on hood, and pull straight up. Took a little but it does come out. I rest my head to keep center of gravity over top of tube and balance, otherwise, once it lets go with the pulling power, you'll probably get hurt falling backwards off top of engine all the way to the ground.
Work smart.