I just took a trip with my 04. 5, 2500, slt, 4x4, long bed, 4-door, towing a 6000 lb rv travel trailer, not a 5th wheel. The trailer has a weight distribution hitch with stabilizer bars. Before leaving I had new Michelin 265 70 r 17 tires put on the rear of the truck and I left the oem (same...