Trans cooler lines, which is which?

[badasS10]

Which of the two lines on the 4.3 radiator is the sending ( from trans to rad.) and which is the returning ( rad. to trans) line? I haven't a clue. I need to re= route my auxillary cooler to be inline with the rad, but I need to know which line is the return line, so I can plumb it in there. Thanks to all you guys for help. I appreciate it.

[Mikz86TA]

On the transmission itself, the Top is the Return and the Bottom is Out to Rad.

[badasS10]

Thanks Mike!:D Greatly appreciated!

[Blazer69]

those quick clips can be a pain so be careful!

[Mikz86TA]

No problem.
IDK on the s-series which they are at the radiator. My only auto is my TA and it only runs an external trans cooler.
Way to test is, when it is cold...start up the vehicle and feel both lines. Whichever one heats up first is the one TO the radiator FROM the trans.

[Blazer69]

i think the bottom is the sending line from the tranny and the upper line is the return line......