My cooler is on the passenger side on the ac condenser. I used the zip tie things so the cooler is tight against it.

I've been reading a lot on this and it seems that when driving below 35 mph, there is not substantial airflow through the cooler. I think this is precisely why it got so hot. Driving uphill at speeds under 25 mph doesn't provide much cooling action through the cooler w/o an auxiliary fan.

Driving at highway speeds in 100 degree heat, the ATF only gets up to about 165. W/o the external cooler, temperatures were as hot if not hotter than the coolant temp at highway speeds which was about 210.

I think it's a fair assessment to say that the b&m keeps the ATF cooler than the radiator's cooler at speeds over 35mph. If you're crawling, climbing, stopping/going in your rig at speeds under 25, the radiator's cooler is going to keep it cooler.

I ordered a fan and plan on installing it asap. I'm going to do the same ride as before and see how hot it gets.