904 Trans oil change

I have never done it before, but what I would do is put the new tranny fluid in a 1 litre jug(something like outboard eng oil, or rear diff oil comes in) They have a lid on them that you can "snip" put a piece of clear tube on the end, that will also fit inside the drain hole. When you squeeze the jug, it will force the trans fluid up the tube and into the converter. Hopefully you will get enough in to be able to button the plug and pan in and start and fill?? Thats somewhat how I change the oil in my outboard boat motor....fill it from the bottom.
Good luck