Ram is launching updated versions of its 2500 and 3500 heavy duty pickup truck with new calibration for their Cummins 6.7-liter diesel engines.

The new calibration is said by Ram to add 15 pound-feet of torque, edging out even Class 4 pickup competitors to a best-in-class 865 pound-feet.

Why are we mentioning such a big vehicle on HybridCars? Even those with heavy towing needs deserve to have access to greener vehicles and this Ram combines heavy towing requirements, relatively decent diesel fuel consumption considering the requirements and, most of all, is a very sustainable choice for the category, being powered by an engine engineered to provide a lifecycle of a humongous number of miles.

Ram claims with this revised engine, 3500 models will offer an increased payload of 7,390 pounds, while maintaining a class leading maximum tow rating of 30,000 pounds. The company calculates its heavy-duty towing capacities using SAE J2807 testing criteria.

Ram actually offers three versions of its 6.7-liter Cummins Turbo Diesel I-6 engine. The first version is paired with Ram’s six-speed manual transmission. This combination delivers 350 horsepower at 2,800 rpm and 660 pound-feet of torque at 1,400 rpm. The second option matches the Cummins to the 68RFE six-speed automatic transmission; with this combo the diesel engine cranks out 370 horsepower at 2,800 rpm with 800 pound-feet of torque at 1,600 rpm.

Dominating torque charts, the 6.7-liter Cummins High-Output Turbo Diesel I-6 for the Ram 3500 is paired with the Aisin six-speed automatic transmission (AS69RC), providing 385 horsepower at 2,800 rpm and torque of 865 pound-feet at 1,700 rpm.

As is customary with bigger pickup trucks like these, Ram did not reveal official fuel consumption estimates. We do expect to see some form of estimates closer to the on-sale date.

Extended maintenance cycle is also a green aspect of this engine with oil change needed only every 15,000 miles, thus using a lot less oil.

Ram started 2015 model year 2500 and 3500 Heavy Duty production this week.