The new Cummins is almost one liter larger, now displacing 6.7 liters in its trademark I-6 configuration. Horsepower is up significantly to 350 horsepower (up 25 from the previous 5.9-liter I-6) and torque is now 650 lb-ft at 1600 rpm, up from 610 lb-ft in the previous gen. This segment has always sold a lot of diesels, but Dodge, in particular, has the strongest diesel relationship with its buyers--as many as 80 percent of all Ram HD sales are made with new owners choosing the diesel. It's worth noting, although the new Cummins is the largest engine among its competitors (the Ford PowerStroke is a 6.4-liter V-8 and GM's Duramax uses a 6.6-liter V-8), it makes nearly identical horsepower and torque numbers; however, the robust I-6 is known in the medium-duty segment for its strength and durability and is used in many heavier-duty applications. To that point, Dodge maintains the new 6.7-liter has longer regular service cycles (every 7500 miles) and a longer predicted engine rebuild life cycle (every 350,000 miles) than anyone has announced to date.

Additionally, and we think most important, this new diesel uses a variable vein turbocharger which includes an industry-first (not just a segment first) exhaust brake to help with its expected heavy-duty loads, allowing for more controlled engine braking and less resulting brake wear. Along with this extremely efficient turbo/exhaust brake package is a new six-speed automatic transmission smart enough to know how to adjust to different empty and loaded torque loads. We especially like the thumb-controller switch that allows the driver to select or lockout specific gears. This is similar to the GM six-speed HD truck transmission, except you don't have to pull the column down into a separate Manual setting. As impressive as the new Cummins is, the biggest part of the power story here is how well the new transmission smoothes out the 1-2 shifts off the line (typically punishing in turbodiesels, empty or loaded) and 2-3 shifts at low speeds and wide-open throttle (think merging onto freeway from a dead stop with an 12,000 pounds trailer). But this powerful, efficient, and smart technology comes at healthy price.

The new Cummins is currently available in 2500 and 3500 model Rams (Regular, Quad, and MegaCab), with the engine option costing $6100 and the six-speed transmission adding another $4175 on top of that. For Dodge's sake, let's hope heavy-duty buyers have plenty of money out there to keep the magic rabbits fed. Of course, when you spread that money out over a 350,000-mile life cycle, maybe there's more of a value story here than you might think.

2008 Dodge Ram HD Cummins I-6
Base price $33,795
Vehicle layout Front-engine, RWD/4WD 3/5/6-pass, 2/4-door, pickup
Engine Engines 6.7L/350-hp /650-lb-ft turbocharged OHV 24-valve I-6
Transmissions 6-speed manual and automatic
Curb weight 6100 - 6600 lb (mfr)
Wheelbase 140.5, 160.5, in
Length x width x height 229.7-249.7 x 79.6-96.0 x 73.9-79.4 in
EPA city/hwy fuel econ 15 / 21 mpg (est)
CO2 emissions 1.29 lb/mile (est)
On sale in U.S. Currently