I run a B&M super cooler.
I plumbed it directly into my transmission, and sealed off the ports to the radiator with some screw in plugs.
It stays around 175 to 180, even on 100+ degree days. If I am hard on it, which I have been, I have only seen it climb as high as 190. Before the cooler, it was well above 200* all the time, when I would get hard on it then, I could peg the temp. gauge.
I installed this cooler back in
2001, still running great, not a leak, or a drip from any of my fittings. The lines i used were stainless steel braided fuel lines I bought through Summit Racing as well.
Sometimes it is needed to run one, sometimes it is not.
But keep this in mind, the cooler it can operate, the better of your are. The transmission fluid will not over heat, and break down as fast, causing premature wear on your parts inside. You can extend the life of your transmission fluid, as well as the life of your transmission.
~F~