The High Output 6.7L Cummins Turbo Diesel engine is the inline-six that turns a Ram Heavy Duty into a serious tow vehicle. It makes 430 hp at 2,800 rpm and 1,075 lb-ft of torque at 1,800 rpm, runs through a ZF TorqueFlite HD 8-speed automatic, and is available on every Ram 2500 and 3500 trim but one. If you already know you want it, our Ram 2500 inventory is where to start.
Two of those figures deserve a second look. Peak torque arrives at 1,800 rpm, which is barely above idle, and peak power at 2,800 rpm, which for most engines is where the interesting part is just beginning. This is an engine designed to do its work low in the rev range and then stop, which is exactly what pulling a heavy trailer up an on-ramp asks for.
| Specification | 6.7L Cummins Turbo Diesel I-6, High Output |
|---|---|
| Configuration | Inline 6-cylinder, turbocharged |
| Displacement | 6.7 liters |
| Horsepower | 430 hp @ 2,800 rpm |
| Torque | 1,075 lb-ft @ 1,800 rpm |
| Transmission | ZF TorqueFlite HD 8AP1075 8-speed automatic |
| Fuel | Ultra-low-sulfur diesel |
| Axle ratio | 3.42 |
| Availability | Optional on Ram 2500 and Ram 3500, every trim except Power Wagon |
Horsepower sells trucks and torque moves them. Torque is the twisting force at the crankshaft, and it is what gets a loaded trailer rolling from a dead stop and what holds highway speed on a grade without the transmission hunting for gears.
At 1,075 lb-ft, this engine has roughly two and a half times the torque of the 429 lb-ft the gas 6.4L HEMI V-8 makes in the same trucks. That gap is the entire reason a diesel HD exists. It shows up in three places a driver actually notices: pulling away from a stop light with a gooseneck behind you, climbing a long grade at a steady throttle instead of a downshift, and engine braking on the way back down.
It also shows up in what the truck is rated to pull, which is the next section, because a torque figure on its own is not a rating.
That third row is the one to read carefully. The same engine is rated differently in the Chassis Cab, at 360 hp and 800 lb-ft, because a commercial chassis is calibrated for a different duty cycle than a pickup. A Chassis Cab number never applies to a 2500 or 3500 pickup, and a pickup number never applies to a Chassis Cab. If you are cross-shopping the two, the engine is the same block and the ratings are not interchangeable.
The Power Wagon is the one 2500 trim that does not offer the diesel at all. It is built around a different job, and its hardware package and the diesel do not go together.
| Application | Output |
|---|---|
| Ram 2500 Heavy Duty | 430 hp / 1,075 lb-ft, optional on every trim except Power Wagon |
| Ram 3500 Heavy Duty | 430 hp / 1,075 lb-ft, optional on every trim except Power Wagon |
| Ram Chassis Cab | 360 hp / 800 lb-ft |
There is no single Cummins tow number. Ratings are set by the whole truck: the model, the cab, the box, two-wheel or four-wheel drive, the axle ratio and the trim. Two real configurations show how far apart the ends sit.
| Configuration | GVWR | Payload | GCWR | Max trailer |
|---|---|---|---|---|
| Ram 2500, 4x4 Regular Cab Tradesman, 8-foot box, 3.42 axle | 11,040 lbs | 3,590 lbs | 27,790 lbs | 20,000 lbs |
| Ram 3500, 4x4 Regular Cab Big Horn, 8-foot box, dual rear wheels, 3.42 axle | 14,000 lbs | 6,060 lbs | 45,000 lbs | 36,720 lbs |
The 3500 in that second row pulls more than 16,000 lbs beyond the 2500 in the first, on the same engine. Dual rear wheels and a heavier chassis are what buy that, not a different diesel.
Three terms are worth having straight before you shop, because they are the ones a rating actually turns on.
GVWR: the ceiling on what the loaded truck itself may weigh, counting everything and everyone in it.
Payload: what you can put in the truck, which is GVWR minus what the truck weighs empty. A trailer's tongue weight comes out of this number, which is why a heavy fifth-wheel eats payload before anyone has climbed in.
GCWR: the limit on truck and trailer weighed together. This is usually the number that decides a real-world towing question.
Bring us the loaded weight of what you plan to pull, not its dry weight, and we will check it against the build sheet on the specific truck rather than against a trim name.
Ram Heavy Duty buyers choose between two engines, and the honest version of the comparison is short.
| 6.7L Cummins Turbo Diesel I-6 | 6.4L HEMI V-8 | |
|---|---|---|
| Horsepower | 430 hp | 405 hp |
| Torque | 1,075 lb-ft | 429 lb-ft |
| Fuel | Ultra-low-sulfur diesel | Gasoline |
| Availability | Optional, every trim but Power Wagon | Standard on every trim |
The power figures are close. The torque figures are not, and torque is what decides how a truck feels with weight behind it.
Take the Cummins if you tow heavy, tow often, or tow far. The gap in what these engines are rated to pull is real, and it is widest exactly where a heavy tower lives. It also costs more up front, and the diesel is an option rather than the standard engine.
Take the 6.4L HEMI if your trailer is occasional and moderate, or the truck spends most of its life hauling in the bed rather than pulling behind it. It is the standard engine on every trim, and our 6.4L HEMI V-8 engine guide covers it in detail. Plenty of Central Indiana buyers who think they need a diesel do not, and that is worth hearing before you buy rather than after.
This engine runs on ultra-low-sulfur diesel.
A 50-gallon fuel tank is optional on a Crew Cab with the long box, and the eligibility note names the trucks it applies to: all Ram 3500 trims and the Ram 2500 Tradesman. If you tow long distances, ask about that tank early, because it is an order-time decision rather than something that can be added later.
Our service department works on the vehicles we sell, this truck included. It is staffed by factory-trained and certified technicians, and engine diagnostic work and full engine or transmission repair are both handled in-house. Schedule service the same way you would for any Ram we sell.
Every new Ram we sell comes with a complimentary first oil change, original owners get free car washes for life, and our service department is open Saturdays. If you run a truck for work, our commercial side is set up for fleet and business buyers.
Powertrain coverage is the term that matters on an engine like this one, and it runs 2 years and 24,000 miles past the basic warranty.
If you are weighing what a diesel HD costs to own, settle the trade-in side first with our trade-in valuation tool. Our Ram specials change monthly, so see our new vehicle specials for the deals running now, and browse the Ram trucks we have to see how they are built.
| Coverage | Term |
|---|---|
| Basic limited warranty | 36 months / 36,000 miles |
| Powertrain limited warranty | 60 months / 60,000 miles |
| Corrosion perforation | 60 months / unlimited miles |
| 24-hour roadside assistance | 60 months / 60,000 miles |
430 hp at 2,800 rpm and 1,075 lb-ft of torque at 1,800 rpm, in the Ram 2500 and 3500 Heavy Duty. In the Ram Chassis Cab the same engine is rated at 360 hp and 800 lb-ft, so never carry a figure between the two.
The Ram 2500 and Ram 3500 Heavy Duty, where it is optional on every trim except the Power Wagon, and the Ram Chassis Cab in its own rating. It is an option rather than the standard engine, and the 6.4L HEMI V-8 is what a truck comes with otherwise.
That depends on the whole truck, not just the engine. A 2500 in 4x4 Regular Cab Tradesman form with an 8-foot box and the 3.42 axle is rated at 20,000 lbs; a 3500 in 4x4 Regular Cab Big Horn form, dual rear wheels and the same axle and box, is rated at 36,720 lbs. Bring us your trailer's loaded weight and we will check the exact truck.
A ZF TorqueFlite HD 8AP1075 8-speed automatic. It is the only transmission paired with this engine in the Heavy Duty trucks.
If you tow heavy, often, or far, yes: 1,075 lb-ft against 429 lb-ft is not a close call, and the tow ratings follow. If your trailer is occasional and moderate, the HEMI is the standard engine and it is genuinely enough truck. Tell us what you actually pull and how often, and we will give you a straight answer.
Ultra-low-sulfur diesel.
A 50-gallon tank is a Crew Cab option paired with the 8-foot box, on all Ram 3500 trims and on the Ram 2500 Tradesman. It is an order-time choice, so raise it before you buy rather than after.
No. The Power Wagon is the one Ram 2500 trim that does not offer the diesel.
GVWR caps what the loaded truck itself may weigh. Payload is what you can put in it, which is GVWR minus the truck's empty weight, and a trailer's tongue weight comes out of that same allowance. GCWR caps truck and trailer weighed together, and it is usually the number that decides a real towing question.
Yes. Our department services the vehicles we sell, this truck included, with factory-trained and certified technicians, and engine diagnostic work and full engine or transmission repair are done in-house. Schedule service the same way you would for any Ram.
