[rotorwrench]

Most automatic transmission have a large enough quantity of oil that it expands to a higher oil level after the car has been driven and is completely warmed up. This can make filling a cold transmission a challenge and is the main reason that they want the oil level checked when the car is completely warmed up. I don't worry about what the capacity is if everything is working. I just make sure it is within the range when the car is completely warmed up. I don't even check it when it's cold unless it won't shift into gear.

I would suggest that you find a way to apply air pressure to the case and see if the air vents out at the vent fitting as it should. I don't think it was meant to be easily removable. The time to test is while the transmission is apart but it should still relieve air pressure while completely assembled.

Make sure that the fluid is coming out the filler and not somewhere else. I've seen them blow out fluid if the vent is plugged so that was certainly a logical thing to check.