Tundra Transmission Cooler Lines

2016 Tundra 4x4 with tow package, I have the factory transmission cooler in front of my radiator.

I plan on doing a transmission fluid exchange.
After draining and re filling what comes out of the pan, I wanted to disconnect 1 of the trans cooler lines to extract a few qts at a time (re filling the transmission case a few qts at a time as well , engine on / off) until the new fluid starts to come out of the trans cooler line.

Will most likely remove the front grill since the cooler lines are right there coming throught the front radiator support.

Id like to pick the line after the fluid goes through the cooler, so im exchanging the fluid in the cooler as well
Does anyone know which of the 2 lines to open up to access the oil after its passed through the cooler?
The pic attached is one I found on the internet that shows the same lines I have.

 

The top hose on the left side is your return to tranny after cooler. I did my today with AMSOIL. Remove that hose and use 3/8 hose, slide on aluminum barb fitting start truck and it pumps through your hose to your catch can pan. Good luck. It is temp sensitive for proper fill. If you have a way to read transmission temp. It’s easy. Look at some videos Here’s one I used. https://youtu.be/cutlJH5KR2Y