Roperteacher

Hey there! I just returned from a 450 mile Round trip in the heat pulling my horse trailer. I ran the AC thw whole way both in Recirc and outside air. Nice and cold as usual. I got home, let the turbo cool, turned truck off while I unloaded and unhooked ( About 15-20 miutes) and when i started it back and turned AC back on, I noticed it was humming just before I parked in the driveway. Was it just re cooling the system or something? I had an 06 do this and Dealer said it was normal. THanks!