When mounting my transmission cooler in my Cutlass, no fancy brackets or any such thing needed to be done. Just look on the passenger side lower corner of the core support. There's a raised area with a hole as shown circled in red in the 2nd attached pic. A basic clip on nut like these
http://www.mcmaster.com/#clip-on-nuts/=lbs5tc fit right over the hole. Just bolt one end of the cooler to that. Line up another hole on the cooler and drill a hole in the core support in the area shown circled in blue. Add another clip on nut and something for a spacer ( you need a spacer because there's no raised area on the core support there ) and bolt on the other end of the cooler.
You now have a cooler that's mounted right behind the bumper as shown in the 1st pic outlined in red. Plenty of air flow right to the cooler!
When I first got my car I didn't want to butcher up my transmission lines when mounting a transmission cooler so I didn't bother with installing one. Then I realized you could just buy the transmission cooler with all the hardware included, and you don't need to do this because they come with the needed fittings. I then noticed there was/is a perfect mounting area for a cooler too. Had I known this stuff before, I would have done it earlier but I read too many internet stories on everyone 'needing' to cut their transmission lines and having 'limited mounting space'. I now see those stories are hogwash!