6.7L Cummins Turbo Diesel: What High Desert Truck Buyers Should Know

Yucca Valley sits at 3,300 feet in the Little San Bernardino Mountains, and the average summer high here is 108 degrees. Those two facts shape how a heavy-duty diesel actually performs for the people who buy them in the Morongo Basin — thin air on the climbs, sustained heat under load. Here’s what the 6.7L Cummins Turbo Diesel does about both, and how to decide whether it’s the right engine for how you actually use a truck.

How Does the 6.7L Cummins Turbo Diesel Perform at High Altitude in Desert Environments?

The 6.7L Cummins Turbo Diesel loses far less power at elevation than a naturally aspirated gas engine because its variable-geometry turbocharger compresses intake air before it reaches the cylinders, partially offsetting the drop in air density. As a rule of thumb, a naturally aspirated engine gives up roughly 3% of its rated output for every 1,000 feet of elevation gain. Turbocharged engines lose meaningfully less — but they aren’t immune. At altitude the turbo has to spin harder to hit the same boost target, so expect reduced loss, not zero loss.

That matters on the Highway 62 climb. Twentynine Palms Highway begins at Interstate 10 near Palm Springs and climbs steadily to Yucca Valley — a sustained grade that asks a truck to make power in progressively thinner air, often in triple-digit heat, frequently with a trailer behind it. A non-turbocharged gas engine has to work harder and rev higher to hold highway speed on that stretch. The inline-six Cummins pressurizes its intake charge instead.

Heat is the other half of the equation. Ram Heavy Duty trucks pair the Cummins with an available Automatic Smart Exhaust Brake and heavy-duty four-wheel disc antilock brakes — the hardware that matters most when you’re managing a loaded trailer on a long desert grade in summer.

What Are the Horsepower and Torque Ratings for the 2027 Ram 2500 and 3500 Cummins Diesel?

The 6.7L Cummins Turbo Diesel produces 430 horsepower and 1,075 lb-ft of torque — Ram’s Best-in-Class available base diesel torque — and it’s the same engine in both the Ram 2500 and the Ram 3500.

Cummins redesigned this engine system for the 2025 model year with a new high-pressure fuel delivery system, top-feed dry service injectors and a new fuel pump, along with a variable-geometry turbocharger that adjusts output to operating conditions faster and more efficiently than the previous generation.

2027 Ram 2500 vs. Ram 3500 Cummins Diesel Specifications

Figures are Ram’s published preliminary maximum ratings for the 2027 model year. Earlier model years carry different ratings. Ask our team which model year is on the lot.

Maximum towing and payload capacity figures are based on properly equipped vehicles and vary by configuration. Do not exceed any weight rating. See your owner’s manual and the vehicle’s door-jamb label for specific capacities.

Should High Desert Buyers Choose the Ram 6.4L HEMI Gas Engine or the 6.7L Cummins Turbo Diesel?

Choose the 6.7L Cummins if you regularly tow heavy trailers, climb sustained grades, or plan to keep the truck for the long haul. Choose the standard 6.4L HEMI V8 if you want maximum bed payload, a lower purchase price, and mostly shorter trips without heavy towing.

That payload point surprises people, so here are the actual numbers on a Ram 2500: maximum payload is up to 4,580 pounds with the gas HEMI — when equipped with the available Payload Upgrade Package — versus 3,990 pounds with the diesel. The iron-block Cummins and its supporting hardware weigh more, and that weight comes directly out of what you can put in the bed. If you’re hauling gravel, tools, or a heavy slide-in camper more often than you’re pulling a fifth-wheel, the gas engine is the more capable truck.

6.4L HEMI V8 vs. 6.7L Cummins Turbo Diesel on the 2027 Ram 2500

Where the diesel separates itself is towing and grade work. Peak torque arrives at low engine speed, so the engine works less to move the same load, and the smart diesel exhaust brake uses the variable-geometry turbocharger to create backpressure that slows the truck on long descents — saving your service brakes for when you actually need them.

The diesel also brings ownership considerations the gas engine doesn’t. It requires Diesel Exhaust Fluid, a urea-and-water solution injected ahead of the selective catalytic reduction catalyst to convert nitrogen oxides into nitrogen and water vapor. It’s emissions equipment, not an additive, and it has its own tank and filler.

What Is the Towing Capacity of the Ram 2500 with the 6.7L Cummins Turbo Diesel?

Properly equipped, the Ram 2500 with the Cummins tows up to 20,000 pounds. Stepping up to the Ram 3500 raises that to 37,020 pounds — but that ceiling requires a specific build: dual rear wheels, a 3.42 axle ratio, 4x4, and an 8-foot bed. Worth knowing before you shop: on the Ram 3500, the High-Output Cummins is offered only with four-wheel drive.

Reaching any published maximum depends on matching cab configuration, axle ratio, and hitch setup, which is why two trucks with the same engine can carry very different ratings. The Ram 2500 uses a five-link coil rear suspension, with a class-exclusive automatic-leveling rear air suspension available to keep the truck sitting level under tongue weight. The Ram 3500 uses a Hotchkiss leaf-spring rear with an available supplemental air suspension. For fifth-wheel and gooseneck work, Ram offers an available Fifth-Wheel/Gooseneck Prep Package with a factory-installed rear-axle structural crossmember and integrated mounting hardware — it’s an option to specify, not standard equipment.

Trailering Technology on Ram Heavy Duty Trucks

On payload, the Ram 3500 carries up to 6,460 pounds with the diesel and up to 7,580 pounds with the gas HEMI — the configuration for heavy slide-in campers and severe commercial loads.

How Much Does a Ram 2500 with the 6.7L Cummins Turbo Diesel Cost?

The number that matters most: the 6.7L Cummins Turbo Diesel is a $12,995 option over the standard 6.4L HEMI V8, and it prices the same on every eligible trim. It went up from $12,595 the prior model year.

Because a heavy-duty truck’s final price depends on cab style, bed length, drivetrain, axle ratio, and equipment group, the honest answer on total cost is that it’s a build conversation, not a single sticker. Our team can price a specific configuration, or you can spec one from the factory.

2027 Ram 2500 Trim Lineup and Cummins Diesel Availability

Manufacturer’s Suggested Retail Price (MSRP) for new vehicles includes manufacturer and distributor options and delivery, process and handling fees, which may be subject to change at any time. MSRP excludes taxes, title, license and dealer installed options, accessories, fees and charges. MSRP is not the dealer advertised price. Dealer price will vary. The dealer sets the final price.

What Warranty Coverage Comes With a New Ram Cummins Diesel at Joshua Tree CDJR?

This is where buying the truck here is different from buying it elsewhere. A new Cummins diesel purchased from Joshua Tree CDJR carries four layers of powertrain protection:

That last one is the one to read closely if you’re buying a diesel, because of what’s on the covered list.

Two details that matter in practice. Your deductible is $0 per claim visit when you bring the truck back to us for a covered repair, versus $250 per claim visit if the work is done elsewhere. And a covered breakdown includes up to $100 per occurrence toward towing and up to $35 per day for up to 10 days of alternate transportation if the truck has to stay overnight.

Two limits to know going in. The coverage is non-transferable — it applies to you as the original purchaser and does not follow the truck if you sell or trade it. And it excludes vehicles modified beyond factory specifications, which for diesel owners specifically means engine tunes, exhaust modifications, lift kits, and non-spec wheels and tires can void it. Claims are administered by Ascent Administration Services, LLC, and repairs must be authorized before work begins. You can review the full lifetime powertrain warranty coverage details before you buy.

Warranty coverage is subject to the full terms, conditions, and exclusions of the written Limited Warranty provided at the time of purchase. Coverage details, deductible amounts, and maintenance requirements are governed by that document. See the dealership for complete details.

Frequently Asked Questions About Buying a Ram Cummins Diesel in the High Desert

Is there still a standard-output 6.7L Cummins, or only the High-Output version?

Only the High-Output version. Ram discontinued the standard-output Cummins, and the High-Output engine — 430 horsepower and 1,075 lb-ft of torque — is now the sole diesel offered in the Ram 2500 and Ram 3500 pickups, paired with the TorqueFlite HD eight-speed automatic. The older 370-horsepower, 850 lb-ft standard-output rating and the AISIN six-speed are no longer available from the factory.

How does the Cummins diesel exhaust brake assist during downhill driving in mountain passes?

The smart diesel exhaust brake uses the variable-geometry turbocharger to restrict exhaust flow, generating engine backpressure that slows the vehicle. That reduces how much you rely on the friction brakes, helping prevent brake fade and pad overheating on long, steep descents with a heavy trailer.

Does driving in high desert heat affect Diesel Exhaust Fluid consumption?

Yes. Heavy loads and high heat raise exhaust gas temperatures and increase nitrogen oxide output, so the engine control module doses DEF more frequently to treat it. Consumption tracks load, idling, and duty cycle rather than mileage alone, which is why it’s worth checking the DEF gauge before a long tow rather than assuming a fixed interval.

What warranty coverage comes with a new Ram Cummins diesel truck?

Factory coverage includes a 3-year/36,000-mile basic limited warranty and a 5-year/100,000-mile diesel powertrain limited warranty, plus Ram’s powertrain limited warranty extension of up to 10 years or 100,000 miles for the original owner on eligible model years. On top of that, eligible new vehicles from Joshua Tree CDJR include a dealer-provided lifetime powertrain limited warranty with no mileage cap, at no additional cost.

How do I schedule a test drive or see Ram heavy-duty inventory at Joshua Tree CDJR?

Browse our Ram 2500 and Ram 3500 inventory online, get directions to our showroom on Twentynine Palms Highway in Yucca Valley, or call our sales team at (760) 228-1818 to arrange a test drive.

Find Your Ram Cummins Diesel at Joshua Tree CDJR

Choosing the right Cummins truck comes down to matching cab style, axle ratio, and chassis to the work you actually do — whether that’s a Tradesman for jobsite hauling, a Rebel for trail access, or a Limited for long highway miles. If you’re not sure whether you need the 3500’s dually chassis or the 2500 covers your loads, that’s a five-minute conversation with our team.

Stop by our showroom on Twentynine Palms Highway in Yucca Valley to compare gas and diesel Ram Heavy Duty trucks side by side, or reach out and we’ll spec one to your requirements.