The MPG of a GMC C4500 Truckby Ken Burnside
GMC's C4500 truck, model name Topkick, is the smallest of GMC's "extra large" commercial grade trucks. The C4500 frame is used for GMC branded dump trucks and busses, and a version of it has been sold as a specialty consumer pickup truck hitting the same general market as the Hummer.
Engines and Mechanical Specifications
The GMC C4500 truck has two engines – an 8.1 liter displacement Vortec V8 engine, and a Duramax 6.6 liter displacement diesel with turbocharging. Both models have a governor built into the engine limiting top speed to 75 mph.
EPA Mileage Ratings
Per Car and Driver, their best guess on the EPA's calculated fuel economy for the turbocharged diesel GMC C4500 was seven miles per gallon. During their driving test and road review, the observed fuel economy was eight miles per gallon with the model given.
The GMC C4500 has a rated towing capacity of 13,000 lbs, and the cargo bed can hold 5,000 lbs. Both towing and hauling cargo near these numbers will reduce the fuel economy below the EPA's rated numbers.