Possible overheating

[w6tractor]

Picking this up from several months ago. Looks like I still don't have this fixed. I have a 72 3/4 ton with 402 BB. All cooling system has been replaced. It has a trans cooler in front of radiator and an aux fan in front of the radiator blowing through the radiator-comes on when AC compressor is running. It has a 160 degree thermostat and HD fan clutch with original fan. It will hold temp until on the road. Temp climbs to over 210 while driving in moderate weather with AC on. Temp comes up to near 230 when slowing down, takes a while to recover back to 210 plus. What could the problem be? Thanks