Hey Sloufoot, Nice Post! Dino oil will start to turn to Fudge at 280 degrees! But, your AMSOIL should be good for 600 degrees! Did you see AMSOIL's Extreme Heat Test on a 2012 Dyna? They strapped it down on a Dyno, shut all the Dyno fans off! They shut off the Bikes Computer Controls for Heat Protection, they ran the Bike up to 550 degrees, let it cool, the results were astounding, the oils viscosity was the same, before & after the test! Amazing! I'd be using AMSOIL'S 75W-110 in the tranny. You should also check out UltraCool. com, BEST oil cooler (heat exchanger), made in Nevada! Tell Earl Boston Jim sent you! Be Safe!