About to install an auto trans cooler and would like to confirm if the is the return line (driver side)

http://i9.photobucket.com/albums/a88/serneckr/WP_000073800x600.jpg (http://s9.photobucket.com/user/serneckr/media/WP_000073800x600.jpg.html)

Start the car up in the morning, while idling, change gears a couple of times, feel the lines, the warm one is from the trans, the cold one is the return line.

ok....will give it a go