I got a B&M Hi-tek cooler that has a 7" electric fan and thermo switch on board, beauty of this thing is you can mount it anywhere! I put mine between the frame rails underneath my radiator in my '59 1/2 ton and plumbed 3/8 hard line along the block - next time I will spend the time to tuck the lines into the frame rails, much cleaner...

There are some really neat 1 or 2 pass heat-sync style trans coolers, check them out at summit, here is a Derale, other vendors make them too, Moroso even has a filtered version

Obviously some cooling is better than no cooling, hot is bad. I bypassed the thermo switch on my cooler and run it full time with the engine, no problems so far

Good luck