I was towing a 5th wheel with boarderline weight as allowed with a 08 silverado. I recently(500 miles ) purchased a Silverado 1500 with the offered Max Towing Package. Essentially this took the place of the 1500 HD of yesteryear. HD Trans(6speed) 6.2 Gas, Hd trans cooler, oil cooler, larger axel, ect ect.the six speed trans seems to be geared very low on one end and high on the 6th. If you take it easy from a light its in 3rd gear at 25 30 mph. Gas mileage is, well, not as good as my 5.3 but 16 to 18 if I don't horse it. HD locking rearend , well thats different, the first time I hit it to pass you knew it was there, no traction loss, just get up and git.integrated electric brake control on dash. I'm submitting this, not tobrag, but to forward info as I recall several questions in the recent past regarding towing with a 1500. Essesentially this is a 3/4 truck in a 1/2 ton truck body. Ride is slightly stiff but not uncomfortable.