GM-GMC: 07 canyon, gmc canyon, tranny lines

Question
I have a 2007 GMC Canyon, and I want to put a transmission oil cooler on it. A
frame mounted type, and I would like to know which is the output line for the
transmission, running to the radiator. I want to put the cooler before the fluid
goes to the radiator, so that the engine doesn't try to run hot when towing my
boat. Thanks for your help.

Answer
My inclination would be to follow the instructions that come with the cooler unit.  To be quite honest I haven't installed a cooler on Canyon...yet.  Typically the transmission lines are like the cooling system hoses.  Hot in the top and cool out the bottom (on most) the tranny lines should be the same in on the top and out on the bottom.  Typically you want to install the cooler after the rad to help cool that extra bit before going back into the tranny.  As for a frame mount, the best cooling will occur when you have a good deal of air passing over the cooler.  However there is more than one way to skin a cat.  I suggest following the instructions that should come with the tranny cooler kit.
Hope this helps