All gas trucks drop down to 10 mpg or worse, when even the lightest trailer is towed. This should be no surprise to anyone. The worst towing fuel economy I've ever experienced, was a bull moose, camp gear and boat on trailer running from eagle Alaska to Wasilla. 7mpg. This was a 3fe powered landcruiser. A dog sht engine.
My buddies 2019 freightliner did better than that, towing over 30,000 lbs of sht through the mountains.
Best fuel economy I've ever experienced towing, was a 16 ft twin axle trailer full of windows, lumber and stove pellets. Stayed at 55-60 mph. It was a 1992 w-350 with 6bt Cummins and a five speed: Almost 17 mpg. Empty, that ugly fkn thing would pull 21 mpg.
Last edited by mainer_in_ak; 07/27/21.
