I think you have to get the back off that model to change belts - you do on my HDKAK 7500.
Make sure nothing is caught in the air intake, which is on the underside at the front, adjacent to the air filter. I've heard of plastic bags or whatnot getting caught and blocking air flow.
Have you checked the coolant level?
Former owner of 2004 American Tradition and several other RVs
Home is in the Ocala Nat'l Forest near Ocala, FL