I'm building a NP205/200 hybrid for my 6x6, which will use two of the 200's output bearing assemblies (the most likely sources of the heat). If my 205 starts overheating, this is precisely what I plan on doing.
I have two things in my favor:
-4.56 gears and 38.5 tires - RPM's should be considerably lower.
-T/C would be bolted to the transmission via a big aluminum (very conductive) adapter, acting as a big heat sink. In a M715, the NP200 sits on its own, with very little to dissipate heat elsewhere.