Sorry about taking so long. Pic is a little dark. Truck is stuck in the garage for a little bit.
Cooler is just behind the cross member, in front of the gas tank.

 

This is on an old body style ls swap truck, but I ended up mounting it there. Iv started doing most my cooler under the car or truck anymore, just helps keep the engine cool and very simple.

 

Cool idea. Do you think it will have enough air to cool the transmission compared to front mount. Mine is behind the FMIC and I have the AC exchanger behind the trans cooler.

 

Iv had a few under the truck already and no problems yet, i think there is quite a bit of air turbulence under the truck while its driving so it gets some air through it, if you do back to back drag strip racing you probably want a fan on it