If you can follow it from the transmission, maybe the image can help you

 

The route it takes is all covered up with other stuff.....

 

Just found this , return apparently is the lower , longer hose / connection #5 :

 

Nope , On my 3.6 , 5AT the "radiator - return - back - to - tranny " hose turned out to be the shorter hose on the driver's side of the car , connection #4 instead of #5 , - picture caption above was a lie !
May not actually matter though if you think about it , as long as you get the trans . fluid through the radiator one direction or another ...but still want to flush it all , including what's in the radiator .