Tiny 1/4” x cut on neck of bottle to blow in fluid. Stand up bottle to do so

Do not use a level on transmission. You will be 2 qts short! And have miss shifts. I did this. Then redid it with the level taped to a side window before jacking it up. By the way my inside filler spout was green. Shorter than the white one. Pan is 5/2012. So may have been changed once before as this is a 2011 ml550. Took 9 qts.
So I changed the fluid. Used 7 qts shell 134 synthetic. Trans slipped. Added two more. All good. I used the infrared temp gun and air compressor. And blew the fluid in. Drilled a hole in a qt cap. Inserted 1/2” tube into it. Connected tube to a ball Valve. Another short section of clear tube. Connected to the transmission. Cut a 1/4” x with an exacti knife in the top neck of the bottle. Use air compressor blow gun to pump and or blow the fluid in. The best method is to use a garden sprayer. Same otherwise. To drain the torque converter I used an Allen key I think about 6mm as a socket does not fit well. Use a crescent wrench on the short end to break the hex key loose. Same for reinstall. Don’t forget the lock tight. I changed mine at 80k miles. Old fluid was black and nasty. I’ll change it again in 40 k miles but with a garden sprayer next time. It will be less hassle. I taped a level on a side window on the car out in the streer then lifted it up in the driveway. Checking that the level on side window was perfectly level.