My buddy has a 2000 Grand Prix GTP, I need to identify which of the two lines running to the radiator from the transmission, is the return line to the transmission, so I can splice a transmission cooler into the line, but the directions are a POS and don't say which of the two is the return line, does anyone know which one is or how to identify the return line?

I know this is a acura message board but it is 2 am and I need help.

 

maybe not the best idea, but you can leave both the lines dissconnected, start the car for half a second, and see which line pumps fluid - thats the feed line, the other one is the return

 

On my '97 GTP is ended up being the top port on the radiator. However, if you read my write up on grandprix.net (not my pictures) I used the lower port out of convenience.

In the end it didn't make any discernable difference as I installed a couple of others at the top port and measured no really difference in the transmission fluid temperature.