I have a 2004.5 Dodge Ram 2500 4x4 with the Cummins Turbo Diesel (325HP/600Ft Lbs TQ), Reg Cab Long Bed, Auto trans. Truck has 240K miles. 2nd gen manifold conversion. Truck has been Kept up with as mechanical issues arose and because of that it runs/drives great. AC blows cold too. No...