Just returned from a 5,000 km (3,100 mile) little vacation across the Canadian Prairie Provinces and into the outer edges of the Canadian Rockies with my new truck. During this trip, I was comparing the performance of my NEW truck to my OLD truck (2004 Nissan Titan - 5.6L). Both trucks came with the full factory installed towing packages. 95% of this trip, my truck was towing a 5,500 lb travel trailer. During the entire trip, I used the Manual mode of the transmission - primarily in 5th gear. The biggest thing that I noticed between the two trucks was that the Titan's torque came into play at a lower RPM than the Sierra's. At 1,500 RPM the Titan had the power to pull whereas with the Sierra anything lower than 2,500 RPM's, the truck was very sluggish. With the Sierra, once I got used to the proper matchup between RPM's and gear's - performed satisfactory. To make things perform well, I was constantly manually shifting gears whereas with the Titan this wasn't really necessary (majority of the time). True, I did miss the Titan's torque, manually shifting the Sierra enhanced its performance and torque performance. Average MPG for this trip was 13 (Imperial gallon) or 10.8 (US gallon) Anyway (without voiding factory warranty) is there anything that one can do to improve low-end torque ???