Mad Matt here with American Powertrain. Nice video on the leak! This a classic case of the vent tube is either kinked or your have a blockage. OR you have too much fluid in the transmission or your transmission is sitting down hill in the back. The shifter box area should not have much fluid in it all. but if it does then the air in the transmission that is whipped up by the gears is looking for a way out. Causing it to push the fluid up to the top. Or again your have too much fluid in the trans.
Thanks
Mad Matt
www.americanpowertrain.com
931-646-4836