Philiparellano

The Vehicle: 2024 sierra 3500 Denali Ultimate (9130 miles on the odometer) The Problem: When I tow I use 93 gallons of fuel to one tank of def. Is this Normal. Total gross weight is 34,640 lbs, I wen’t to a truck spot to get weighed on their scale. I average 6.2 mpg(576 miles before I need more def). I have been back and forth with GM and the dealership. I am pursuing a vehicle repurchase. Please let me know if this is reasonable def consumption. This only happens when I tow. I can go hundreds of gallons of fuel before needing def when I am driving without a load.