I have an '02 2500 Quad Cab 4x4 with the H. O. engine and 6sp transmission. I noticed that when towing my 7000 pound travel trailer my exhaust temps go up then towing in 6th at about 60 mph. The increase is about 100 degrees. This seems to make sense(less gear, more fuel, higher exhaust temps). Is there anyone else pulling a similar wieght, and what gear are you using at highway speeds?