Tranny coolers are not necessary in my opinion. We have had many GM 3.8'* and 3.1'* with the 4t60e and 4t65e trannies, and have never had a tranny fail. Not even in the GTP making 400hp. Unless you drive in a lot of stop and go traffic, or live in a warm climate (arizona, texas, etc.). The operational temperature for our trannies are 180-230 degrees. Anything below 180 is dangerous, and anything over 230 is dangerous. From my monitoring of the GTP on the Autotap, I have never seen it go over 200 degrees and that was with the full throttle runs along with a 1 hour drive at lots of different speeds, and 2 lane road passing, etc..., and it is making 400hp and 450ft.lbs torque. In my opinion coolers are not necessary. You can get one if you want, but we aren't going to put any on our cars in any point in the future. If it cools below 180 degrees it may do more harm than good.

That makes sense. You would think the people at Pontiac would include a tranny cooler as a stock option if one was needed. Maybe i dont need one. All i know is when i installed my 180 degree it did nothing. I am just trying to get the temp down a little, so i am willing to try anything (that does not void my warantee)

I have always run with trani coolers in my cars. My Bird is 24 years old and still going strong.
The rule of thumb is that for every 10 degree F drop in trani temp you double the life of the trani fluid. I suppose if you change it often it helps just as well.
My trani temp, as measured with a heat gun at the inlet and outlet of the cooler never seems to go above 180 F and the cooler drops the temp to about 160 F.
Cool eh.

When the weather is cool, the 180 stat stays around 180 but in the warmer weather now it runs up to 195 F. I suspect we need a larger capacity radiator to keep the temps down regardless of the stat.