My 2007 Diesel dually with the 6.7L engine got hot going up the Grapevine towing my 23 foot Weekend Warrior. This trailer weighs probably less than 9,500 lbs fully loaded. Should it be getting hot with amount of weight? Also, What type of fan do you have on your diesel? the stock clutch fan, a flex fan or an electric fan or combination? The temperature outside was approximately 95 degrees.