2021 Ram Heavy Duty Has Segment-Leading Towing Capacity Photo: FCA The Ram Heavy Duty has improved its capabilities and technology offerings for the 2021 model year. With its latest upgrades, the truck now has the highest available gooseneck towing capacity in the industry at 37,100 pounds. Photo: FCA To achieve its best-in-class tow rating, the 2021 Ram Heavy Duty must be equipped with the 6.7-liter High-Output Cummins Turbo Diesel I6 engine. This engine delivers 430 horsepower and a best-in-class diesel torque of 1,075 lb-ft, which is an improvement of 75 lb-ft over the previous model year. The truck now has fully boxed rails and an enhanced rear-axle structural crossmember to handle the higher towing capacity. Optional fifth-wheel pucks along with gooseneck center castings and bolt plates are included in the production box floor as well. In addition, the truck offers two trailer connectors at the rear, making it easy to wire your trailer.