those tranny coolers really suck! they wouldnt cool down my 4.7 tundra at all!! i was running 2 of them and one of them had a fan mounted behind it theres just not enough space in between the fins it doesnt flow good. i went with this cooler from amazon i mounted a fan behind and it works crazy good its hard to heat up the tranny even running it hard in the sand 100+ weather and when it reaches 220+ degrees i idle it and it cools down quick.
in my territory there not to much hot days usually, and tundra has a bit bigger gearbox i suppose....So far - around 30-40 degs outside everything is fine - Ill wait more for summer to test it