Dodge Ram Diesel Specifications

Dodge Ram trucks equipped with a Cummins diesel engine has superior towing capacity.

Dodge Ram pickup trucks are powered by Cummins diesel engines. Since 2007, the 2500 and 3500 Ram series trucks have been equipped with the 6.7-liter Cummins diesel. Dodge Ram trucks are the leaders in towing and payload capacities due to its torque capabilities that give the truck its hauling power.


The Columbus, Ind.-based Cummins Inc. signed a contract with the Dodge Division of the Chrysler Corporation in 1989 to supply Dodge light-duty trucks with diesel power. Dodge was a late-comer to diesel power. Chevy and GMC trucks have been equipped with diesel engines since 1978 and Ford climbed aboard in 1983. The Cummins 5.9-liter (359 cubic inches) all-iron block in-line six-cylinder diesel engine was the first to power Dodge trucks. The 5.9-liter version was replaced by the 6.7-liter diesel in 2007 to meet tougher federal emission standards, according to

Dodge/Cummins Relationship

Although Cummins produces diesel engines for Dodge’s light- and medium-duty trucks, the company built its engines based on the same principles as manufacturing a diesel for an 18-wheel tractor-trailer rig. The concept ensured durability and a 300,000-mile lifespan before the engine’s first overhaul. Dodge responded by toughening its trucks’ chassis, suspension, transmission and rear axle to accommodate the added stress and demands placed by the diesel that essentially was over-engineered for a light-duty truck. The result was not only a durable engine, but a truck chassis and drivetrain that could outlive its competitors by years.

6.7-Liter Diesel Features

Cummins and Dodge saved on costs with the changeover from the 5.9-liter to the 6.7-liter engines by ensuring that 40 percent of the parts in the 6.7-liter came from the 5.9-liter model. The 6.7 diesel is equipped with an integrated exhaust brake to improve the control of the truck while towing. The engine’s redesigned fuel injection system minimized noise and vibration which is common in diesel engines. The engine was designed to meet government emission standards through 2013.


The 6.7-liter (408 cubic inches) is a 24-valve in-line six-cylinder turbocharged engine. It features a 4.21-inch bore and 4.88-inch stroke. Compression ratio is rated at 17.3:1. Fuel is delivered through an electronically-controlled Bosch direct injection system. The engine is matched with a five- or six-speed automatic transmission or a six-speed manual. The Ram 2500 and 3500 series trucks equipped with the 6.7-liter diesel have an 11.50-inch rear axle.


The 6.7-liter diesel generates 350 horsepower. Equipped with an automatic transmission, the engine wields 650 foot-pounds of torque, which is the twisting force generated to give Dodge its hauling capability. The truck equipped with a manual transmission generates 410 foot-pounds of torque. Towing and payload capacities matter the most in a truck. The 2500 and 3500 series diesel trucks equipped with a manual transmission have a maximum towing capacity of 13,350 and 14,100 pounds respectively. The 2500 with manual transmission can carry a 2,490-pound payload and the 3500 a 5,050-pound payload. Automatics fare better due to 450 foot-pound rating. The 2500 can tow 13,450 pounds, and the 3500 up to 17,000 pounds. Payload capacity for the 2500 is 2,590 pounds, and the 3500 can haul 5,130 pounds.