Well there is a "cooler" so to say, already on the car. It's a bit of extra metal line coiled up somewhere, on mine it's under the pump at subframe level. It would be pretty easy to install a cooler being you'd put it in the suction line, and there is already rubber hose there that you could splice. But I don't know how much longer it would prolong the fluid life, it really only gets hot in the summer months here in MI. Depending on the actual temperature the fluid reaches, it may be worth it for people in places with hotter climates. Someone should stick a probe in the reservoir after a long city drive on a hot day and see what were really getting. I'm sure just like transmissions, anything above 220 is pushing it.
