My 931A2 has been a workhorse for me; I turned up the fuel just a little bit, and increased the airflow (the air filter with the wire cage around it) which made a HUGE difference in reducing EGTs. I flushed the trans oil out and after complete filter changes filled it with Dexron III. It pulled a 53K-lb load up the Tehachapi grade in August heat with no issues; speed was reduced to 1st gear up one stretch but there were no overheating issues with anything (I keep a close eye on EGTs, as well as engine & trans temps).
My heaviest load was 58K-lbs between NV & southern Utah; this truck has made several dozen trips loaded up the mountain passes to our property in southern UT, where it currently resides. The first trip was when I discovered that the fan clutch wasn't engaging....but after that was fixed, I never had another issue with this truck. It's pulled & hauled reliably, even with a broken low-range gear in the transfer case (to be fixed soon).
Just with the minor tinkering I've done to the 6CTA motor, I've really livened it up & gotten a lot more pep out of it, making the truck a real workhorse. What Wes did with the MRAP radiator/cooler combo is even more useful; if I keep my 931A2 I'll do this to lower the EGTs even more and make it even more responsive over the long term.