What is the best diesel truck engine for towing?

There is no single best diesel engine for every towing buyer. The right choice depends on payload, axle ratio, transmission, cooling package, truck condition, service history, trailer weight, and the kind of towing you do. Cummins, Duramax, and Power Stroke trucks can all be good tow rigs when they are matched correctly and maintained well. Do not shop by engine reputation alone. Check the door-jamb payload sticker, hitch setup, brake controller, tire ratings, service records, transmission behavior, cooling stability, and whether the truck has been tuned or deleted. A well-documented truck that fits your trailer is usually better than a famous engine in a neglected chassis.