I have a 06 silverado 1500 4.8 liter engine 3:23 rear gear. I bought a 2009 V-Lite by Forest River. dry weight 4900 lbs, loaded around 5500 lbs. I was or have pulled it in the tow mode. A friend who has been pulling a camper for about 25 years says that the truck will pull better if I put the gear shift in number 3 while in the tow mode. I admit the truck does not seem to work as hard and will not downshift as much as when it is in the overdrive mode and in tow mode. I checked the motor RPM's and they were basically the same in either mode. I do have a tranny cooler on the truck, and it is rated for 6000 lbs. . I have been getting about 10 MPG while towing. I am kicking around the ideal of getting something bigger motor wise, but I don't want to hurt the transmission either if I stay with what I got. I was wondering if anyone out there tows with the 4.8 liter.:shrug: please help.....