I've often wondered the same thing, it's a pain in the *$n. You would think that they would design somthing so simple, a little easier. I hope someone has figured somthing out, cause it makes a terrible mess.
I use a hose that fits inside the hose , I think half inch O.D. {Plastic hose },Take filler tube off hose stick it in and drain and drain into bucket tied to combine .
Yes, I know of a mechanic that works at a CASEIHC dealership who designed a kit to do this, and I believe he is selling them. His home phone numbers are 204-782-6199 or 204-735-2200. His name is Marlin.
I have a 2166 and modified the rotor oil case drain with a brass valve suitible for oil and hose to get below the chassis. I cut the hose below the dipstick and installed a brass tee with a valve connected to it and hose barbs out of the top and side of the tee and the valve. then just connect the hoses with hose clamps. The dipstick will still be accurate because it stays at the same height. I used a wire tie to secure the handle of the valve so it wouldn't get opened accidentily.