The 6.6L Duramax is a turbo-diesel V8, engine code L5P, rated at 470 horsepower and 975 lb-ft of torque. It is paired with a 10-speed automatic transmission. Chevrolet offers it as an option on the 2026 Silverado 2500 HD and 3500 HD pickups, where a 6.6L gas V8 is the standard engine. If you are shopping for one of those trucks here in Central Indiana, the choice between the two engines comes down to how much you tow and how much you carry.
The 6.6L Duramax is rated for more horsepower and far more torque than the standard gas V8 in both the 2026 Silverado 2500 HD and 3500 HD. Here is how the two engines compare, line by line.
| Specification | 6.6L gas V8 (standard) | 6.6L Duramax (optional) |
|---|---|---|
| Engine | 6.6L V8 gasoline | Duramax 6.6L Turbo-Diesel V8, code L5P |
| Horsepower | 401 at 5,200 rpm | 470 at 2,800 rpm |
| Torque | 464 lb-ft at 4,000 rpm | 975 lb-ft at 1,600 rpm |
| Transmission | 10-speed automatic | 10-speed automatic; on the 3500 HD also a 10-speed automatic with integrated power take-off |
| Rear axle ratio on the 3500 HD | 3.73 | 3.42 |
| Fuel | Gasoline | Diesel, B20 compatible |
| Drive | 2WD or 4WD | 2WD or 4WD |
The diesel also reaches its rated torque at a lower engine speed than the gas V8. On a single-rear-wheel 3500 HD, the diesel raises the conventional towing rating for Crew and Double Cabs and the gross vehicle weight rating for Crew Cabs. What you give up is some payload: in every matching 3500 HD Crew Cab, the gas V8 carries more.
Both 2026 Silverado HD pickups, the 2500 HD and the 3500 HD, can have the 6.6L Duramax. This table shows each truck's whole 2026 lineup: trims, cabs, rear wheels and drive.
| Truck | Trims | Cabs and beds | Rear wheels | Drive |
|---|---|---|---|---|
| 2026 Silverado 2500 HD | Work Truck, Custom, LT, ZR2, LTZ, High Country | Regular, Double and Crew Cab | Single | 2WD or 4WD |
| 2026 Silverado 3500 HD | Work Truck, LT, LTZ, High Country | Regular, Double and Crew Cab | Single or dual, except the Standard Bed Crew Cab, which is single only | 2WD or 4WD; High Country is 4WD Crew Cab only |
The diesel is an option, and whether you can get it depends on the cab, trim and build. Get an overview of the 2026 Chevrolet Silverado HD, then search our new Chevrolet inventory for a Duramax build. Our listing for each truck shows whether it has the diesel, or you can ask us.
With the 6.6L Duramax, a 2026 Silverado HD is rated to tow up to 20,000 pounds on a conventional ball hitch, and some builds go higher on a 5th-wheel or gooseneck hitch. These are maximum trailer ratings, which Chevrolet calculates for a standard-equipped truck with a driver and the required trailering equipment. The weight of optional equipment, passengers and cargo reduces what the truck can tow.
Below are the 2026 conventional ratings on a ball hitch, with the gas V8 beside the diesel for each 3500 HD build.
| Truck and build | 6.6L gas V8 | 6.6L Duramax |
|---|---|---|
| Silverado 2500 HD Crew Cab long bed, Max Trailering Package | - | Up to 20,000 lb |
| Silverado 3500 HD Crew or Double Cab, single rear wheels | 16,000 lb | 20,000 lb |
| Silverado 3500 HD pickups with dual rear wheels | 17,600 to 18,700 lb | 20,000 lb |
| Single-rear-wheel Silverado 3500 HD Long Bed Regular Cab | 14,500 lb | 14,500 lb |
On a 5th-wheel or gooseneck hitch, these two 2026 diesel builds are rated higher than on a ball hitch.
Before you buy a vehicle or use it for trailering, carefully review the Trailering section of the Owner’s Manual.
Ratings depend on the exact build and hitch, so bring your trailer's loaded weight when you shop, and we can match it to the right truck.
| Truck and build | Rating |
|---|---|
| Silverado 2500 HD 2WD Crew Cab long bed, Max Trailering Package | 22,070 lb with a gooseneck or 5th-wheel hitch |
| Silverado 3500 HD 2WD Regular Cab Long Bed, dual rear wheels, Max Trailering Package | 32,000 lb with a 5th-wheel hitch; 36,000 lb with a gooseneck hitch |
The gas V8 carries more payload than the diesel in every matching 3500 HD Crew Cab, even though the diesel raises the gross vehicle weight rating (GVWR) of single-rear-wheel Crew Cabs. On those single-rear-wheel Crew Cabs, the diesel's GVWR runs from 11,750 to 12,250 lb, 550 lb above the gas V8's in every configuration. A dual-rear-wheel 3500 HD has a 14,000 lb GVWR with either engine.
We sell both the Silverado 2500 HD and the 3500 HD here at Ed Martin Chevrolet. Check our new Chevrolet specials, then get a trade value estimate on your current vehicle. You can arrange financing through our auto finance center, and when you are ready, schedule a test drive and tell us how you plan to tow.
We are at 5400 Scatterfield Road, Anderson, Indiana 46013, in Madison County, northeast of Indianapolis. If you have questions before you visit, ask our team about a diesel Silverado HD.
It is rated at 470 horsepower at 2,800 rpm and 975 lb-ft of torque at 1,600 rpm in both the 2026 Silverado 2500 HD and 3500 HD. For comparison, the gas V8 makes 401 horsepower and 464 lb-ft.
You can get it in either 2026 Chevrolet Silverado HD pickup, the 2500 HD or the 3500 HD, as an option in place of the standard gas V8.
A 2026 Silverado 3500 HD with the diesel has a maximum conventional trailer rating of 20,000 pounds in every pickup build except the single-rear-wheel Long Bed Regular Cab, which is rated at 14,500 pounds. A gooseneck hitch brings the rating to 36,000 pounds, but only on the 2026 3500 HD 2WD Regular Cab Long Bed with dual rear wheels and the Max Trailering Package. That truck is rated at 32,000 pounds with a 5th-wheel hitch. A diesel 2500 HD long-bed Crew Cab with the Max Trailering Package is rated for as much as 20,000 pounds on a conventional hitch. Chevrolet calculates these maximums for a standard-equipped truck with a driver and the required trailering equipment, and optional equipment, passengers and cargo all reduce them. Browse our new Chevrolet inventory for a truck that suits your trailer.
Yes. It is B20 compatible, so it can run on diesel blended with up to 20% biodiesel.
