OK, one of the forums I was on always encouraged adding a trans cooler; even if the truck was equipped with a factory cooler. Their explanation was the factory setup is inadequate. It didn't matter if the OP was having wiper issues, an aftermarket trans cooler would fix that too... I have been watching my trans temps just to see what I get too, and even loaded heavy (trailer pushing 10k pounds); the most I have seen to date is about 180*F. Most of the time it runs about 140* to 150* when just driving around. None of these temperatures seem high to me? I want to remember the trans warning light is preset at 235*F? So my question is this, if the trans isn't running hot; why would you need to add another cooler?