just get a tube cutter, and cut the top hardline a few inches from the fitting. Then plumb your cooler inline with that.
I would use some ss hoses, the rubber doesn't do it for me anymore.
Then use two hose clamps on each side of the connection to keep mr. leak from starting.
I use fuel injection clamps because they don't back out like a regular hose clamp.
Zip tie your tranny cooler to the a/c condensor, I won't tell anyone.