Detroit DD15 Engines — 14.8L Heavy-Duty Diesel

The DD15 is engineered primarily for over-the-road line haul, where its fuel economy and integrated powertrain pairing with Detroit's DT12 automated transmission make it a favorite of fleets. It is the volume engine in the Freightliner Cascadia, the best-selling Class 8 tractor in North America, and also appears in Western Star vocational and highway trucks. Ratings typically run from about 400 to 505 HP with torque suited to heavy over-the-road loads.

That enormous installed base means a deep supply of replacement engines, from low-mileage accident takeouts to professionally remanufactured units, keeping both pricing and lead times attractive for owner-operators and fleets alike.

A low-mileage used DD15 offers the fastest, lowest-cost return to service, and we dyno-test or verify condition where possible. A remanufactured DD15 is restored to OEM specification with new bearings, seals, gaskets and reconditioned heads and crankshaft, carrying the strongest warranty and longest service life. For a truck you plan to keep running hard, remanufactured is usually the best long-term value.

The DD15 is a strong engine, but high-mileage units can develop wear in areas such as the EGR system, turbo actuator, fuel injectors and the camshaft/rocker assembly. A remanufactured or freshly rebuilt DD15 addresses these areas, and a dyno-tested used engine reduces the risk of buying an unknown. We discuss the history and condition of every unit we quote so you can buy with confidence.