When you are shopping for used diesel trucks for sale, you will likely hear names like Duramax, Power Stroke, and Cummins. If you aren’t familiar with them, these are the names of the engine families used by GM, Ford, and Ram in their most powerful diesel trucks. Why does this matter? Because each of these three diesel engine families is designed differently and has its own dedicated fan base that swears by it. When you want maximum performance, it is important to look under the hood and understand exactly what is powering the truck you are interested in. However, it can all seem a little overwhelming if you are new to the world of diesel pickups, so here’s what you need to know to sound like a pro when you start shopping for your diesel truck.
The Big Three
The vast majority of the used diesel trucks for sale come from the Big Three American manufacturers: GM, Ford, and Ram. If you aren’t a car person, you may be wondering, “what about Chevy, GMC, and Dodge?” Well, Chevy and GMC both belong to GM and share the same basic truck designs and engine technology. Just about everything that you learn about Chevy diesel trucks will also apply to GMC diesel trucks, and vice versa––the only real difference is that GMC models are a bit more upscale, and Chevy models are a bit more affordable. As for Dodge, it doesn’t make trucks anymore. At one point, Dodge owned Ram, but in 2010 the two parted ways, with Ram building trucks and Dodge focusing on muscle cars.
Each of the Big Three has its own diesel engine family that is found in its heavy-duty pickups. The GM brands (Chevy and GMC) both use Duramax engines, Ford uses Power Stroke engines, and Ram uses Cummins engines. Now, technically, Duramax and Power Stroke are brand names owned by GM and Ford, while Cummins is a separate company that produces diesel engines for a variety of manufacturers. Cummins engines can be found in a large number of commercial trucks, agricultural equipment, military vehicles, and even ships, but Ram is the only consumer pickup manufacturer to offer the legendary Cummins inline-six diesel engine.
The Duramax Family
If you are searching for a used Chevy or GMC diesel truck, then you will probably find yourself looking at Duramax engines. The Duramax family was introduced in 2001 with the first generation of the Chevy Silverado HD, replacing the old Detroit Diesel offered in the Chevy C/K Series trucks. These engines are built in Dayton, Ohio, by DMAX, which has GM as its majority shareholder. The remainder of DMAX shares are owned by the Japanese truck and engine manufacturer Isuzu, which contributed its expertise to the Duramax design.
Every Duramax engine offered for the Chevy Silverado HD and GMC Sierra HD has been a large 6.6L V8 turbo-diesel, but the specifications have changed over the years. The original 2001 Duramax engine was the LB7, which offered 300 hp and 520 lb-ft of torque. However, power output has crept up over the years, and the latest Duramax L5P, which is scheduled to be introduced on the 2024 Silverado HD and Sierra HD, generates an incredible 470 hp and 975 lb-ft of torque. This means that it is important to check the specs of whatever used truck you are shopping for to see exactly what version of the Duramax it has.
The Duramax name has also been used for some smaller engines found in light-duty GM trucks. Since 2020, the Silverado 1500 and Sierra 1500 have offered a smaller 3.0L I-6 Duramax, which generates a lower 277 hp and 460 lb-ft of torque. The midsize Chevy Colorado and GMC Canyon are available with their own Duramax, which you can find in used models from 2015 to 2022. This engine is a 2.8L I-4 with just 181 hp and 369 lb-ft of torque. Interestingly, despite using the Duramax name, both of these smaller engines were designed by GM subsidiaries in Italy, not by DMAX. The 2.8L was developed by VM Motori, while the 3.0L was produced by Opel.
The Power Stroke Family
When it comes to used Ford diesel trucks, Power Stroke is the name of the game. The Power Stroke engine family is older than the Duramax family, dating back to 1994, and has covered an even wider range of different engine sizes. In fact, the Power Stroke name was originally used for a collection of engines built by Navistar International for Ford before Ford began designing its diesel engines in-house in 2011. If you are shopping for used Ford trucks, then you are primarily going to be looking at the 6.4L and 6.7L Power Stroke engines offered in Ford Super Duty models, although you may also find the older 6.0L Power Stroke for the Super Duty and the short-lived 3.0L Power Stroke offered in the F-150 from 2018 to 2021.
The 6.4L Power Stroke was introduced in 2008 to replace the problematic 6.0L in the Super Duty less than three years after that engine debuted. The 6.4L was the last Power Stroke from Navistar and was a traditional V8 turbo-diesel that produced 350 hp and 650 lb-ft of torque, making it comparable to the Duramax from the same era. In 2011, it was replaced by the Ford-designed 6.7L V8, which was code-named “Scorpion” and offered significantly more power. The original 6.7L offered 400 hp and 650 lb-ft of torque, but the latest version now offers 475 hp and 1,050 lb-ft of torque. There is even a new High-Output 6.7L Power Stroke for the 2023 Super Duty with an unbelievable 500 hp and 1,200 lb-ft of torque, though it will take a while before trucks with this engine start showing up on the used market.
The Cummins Family
Because Cummins is an independent company rather than a trademark, it has a much longer history than Duramax or Power Stroke. In fact, Cummins was founded in 1919 and has been building diesel engines since 1933. It got its start producing engines for railways and commercial trucks and was an industry leader by the time Dodge approached it to build a diesel engine for the 1989 Ram pickup. Up until that point, diesels had a mixed track record in smaller trucks, but the 5.9L I-6 turbo-diesel that Cummins came up with quickly became a legend for its power and reliability, forcing GM and Ford to develop diesel trucks of their own.
When shopping for used Ram trucks, you can still find updated versions of the 5.9L Cummins B Series. The original 12-valve design was replaced by the more modern 24-valve ISB variant in 1999, which remained in production until 2007. The final versions of the 5.9L produced up to 325 hp and 610 lb-ft of torque, making them solid options even today. However, Ram wanted even more power and commissioned a larger 6.7L version of the basic ISB design. This produced 350 hp and 650 lb-ft of torque when it debuted, and the latest 6.7L High Output in the 2022 Ram 3500 provides 420 hp and 1,075 lb-ft of torque. Because the Cummins engines use a perfectly balanced straight-six design rather than a V8 like the Duramax and Power Stroke options, they are known for their smooth power delivery.
Also, unlike GM and Ford, Ram has not diluted the Cummins name by applying it to less-powerful options. Every Ram with a Cummins is a heavy-duty pickup with a large I-6 turbo-diesel. While the Ram 1500 was offered with a smaller 3.0L V6 turbo-diesel from 2020 to 2023, that engine was branded as an EcoDiesel. Interestingly, it was designed by the same VM Motori that was responsible for the 2.8L Duramax engine, as GM sold all of its shares in the engine designer to Ram’s parent company, Stellantis, in 2013.
The Best Used Diesel Truck?
The Big Three manufacturers and their diesel engine families are all solid choices when you buy used. The Duramax, Power Stroke, and Cummins names all have their fans, and for good reason. Each of them has been the best-in-class option at different times, and all three of them offer impressive performance and reliability. Deciding which one is best for you will depend largely on which model year you are shopping for and how much performance you need. The good news is that you are now well on your way to being a used diesel truck expert and have the knowledge you need to find the right used diesel truck for sale.