A transmission doesn't use fluid
A transmission doesn't use fluid or goes through fluid let's say like an engine might burn off engine oil. It's either in the pan or it's leaking out of the pan or seal. In most cases if you check your tranny fluid after running it down the road twenty miles or so, operating temps, and it shows full on the dipstick after inserting it a few times to double check yourself. Look on the back of the dipstick not the front for the true level. If your level is going down, then it's sitting on your driveway after being parked there for any time. To remove the excess you can either suck it out from the top as mentioned or loosen the rear pan bolts to let a little out. Don't run it overfilled, will cause damage to the tranny if it is in continued use.
"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan