Got it. Didn't notice you had the cutaway.
BTW - the PCM will retard power when the transmission gets too hot. Sounds like you are a candidate for a larger cooler. With the torqueshift, you should not need to re-gear for low-speed performance.
The TruCool Max 40,000 GVW cooler is designed for 1/2" lines like the TorqueShift has, and fits in place of the stock cooler if you trim away the passenger side cooler support.
And yes, you have the Dana 70 rear, which is rated for 8500 pounds on the DRW cutaway.