I changed the trans oil in my '86 yesterday, and figured I could share what I learned. Using a harbor freight suction cup to stick a funnel to your quarter window with a hose on it is a fantastic solution:
It's probably the best idea ever, until you realize the Germans had some anti-gravity technology applied to the transmission fill plug hole and it just dumps out into the drain pan you left under the car (you DID leave the pan until you were finished, right?). In retrospect, the suction cup idea might have worked with a smaller diameter hose, but the (fortunately empty) funnel fell off the window right after I took the above photo.
In the end, I went to the parts store and bought one of the pumps that screws into the quart bottle, but it wanted to leak the same amount that it actually put into the transmission, so back to another store to get a suction pump, which I suppose I had seen before but never considered, and it ended up being the best solution:
I literally had the oil back in the transmission 30 minutes after getting home with the suction gun, after spending several hours with sub-standard methods and tools.
I really did want that suction cup idea to work though....