2000 Chevy K3500 Crewcab 4x4 Dually 6.5l TD auxiliary coolers

So I am getting ready to full-time RV and wanting to make sure my engine has the best chance to survive. I am upgrading the fan and clutch to the duramax fan through SS Diesel Supply, along with the 180° thermostats. Delco made an electric fan for HD cooling but there seems to be two factory coolers where it needs to go. There are actually a total of 3 auxiliary coolers in front of the condenser and I am not sure what the third one is. 1st two should be engine oil and trans fluid, the 3rd might be power steering, but not sure. Anyone else dealing with this?

You are correct, engine oil, tranny, PS....