What engine is in the Silverado 3500HD?
The Silverado 3500HD is offered with two engine options: a 6.6-liter V8 gasoline engine (L8T) and a 6.6-liter Duramax turbo-diesel V8 (L5P).
Chevrolet’s heavy‑duty pickup is built for serious work, and the choice of powertrain affects towing capacity, payload, and overall driving feel. Below is a snapshot of the two engines currently available for the Silverado 3500HD and how they differ in performance and usage.
Engine options for the Silverado 3500HD
Two powertrains cover different job profiles—one prioritizes straightforward performance and accessibility, the other emphasizes torque for heavy towing and sustained workloads.
6.6-liter V8 gasoline (L8T): produces about 401 horsepower and 464 lb-ft of torque, paired with a 10-speed automatic transmission. This option is favored for drivers who want solid everyday capability with strong payload support and easier maintenance.
6.6-liter Duramax turbo-diesel V8 (L5P): produces about 445 horsepower and 910 lb-ft of torque, paired with a 10-speed automatic transmission. This option is preferred by buyers who tow heavy trailers or regularly haul substantial loads, especially at low RPMs.
Both engines are designed to drive the heavy-duty drivetrain and are commonly paired with four-wheel drive options and the same 10-speed automatic transmission. Availability can vary by trim, cab/bed configuration, and market.
Performance considerations and configuration notes
Engine choice directly influences towing capacity, fuel economy under load, and maintenance profile. The Duramax diesel delivers far higher torque at low RPM, which translates to stronger highway towing and quicker acceleration when pulling heavy trailers from a standstill. The gasoline L8T, while less torque-dense, provides ample power for typical work‑truck duties and can offer lower operating costs in some use cases and markets.
Transmission and drivetrain details
Both powertrains are paired with a robust 10-speed automatic transmission and are commonly configured with heavy-duty axles and available four-wheel drive to maximize off-the-line capability and load retention on challenging terrain.
Availability by model year and configuration
GM has offered these two engines in the Silverado 3500HD across recent model years, with the Duramax diesel historically favored for the heaviest towing and payload applications. The gasoline L8T remains a strong, all-purpose option for users who need solid capability without the diesel’s emphasis on torque. Exact availability and output can vary by model year, trim level, cab configuration, bed length, and market regulations. Always check the current spec sheet for your vehicle’s exact configuration.
Summary
In the Silverado 3500HD, you choose between two powertrains: a 6.6-liter V8 gasoline engine (L8T) delivering about 401 hp and 464 lb-ft of torque, and a 6.6-liter Duramax turbo-diesel V8 (L5P) delivering about 445 hp and 910 lb-ft of torque. Both pair with a 10-speed automatic transmission and are tailored to different workload demands—from everyday heavy lifting to maximum-totion towing. Your best choice depends on how you plan to use the truck and the level of towing or payload you require.
What are common 3500HD problems?
Here's what drivers often report: Transmission slipping while on the highway. Long pauses or hard clunks when shifting gears. Fluid leaks showing up under the truck.
Is the 2025 6.6 Duramax a good engine?
The 2025 6.6L Duramax turbo-diesel engine is praised for its immense power, producing 470 horsepower and 975 lb-ft of torque, making it ideal for heavy towing and hauling. Reviewers highlight its strong performance, particularly with loads, and the smooth, quiet ride provided by the Allison 10-speed transmission. While the engine itself is highly regarded, some owners have reported issues with the vehicle's electronics, such as connectivity problems, and some have noted that the modern diesel requires proper, diligent maintenance.
This video shows the 2025 Chevrolet Silverado 2500 HD High Country Duramax in action, including an acceleration test: 0:19Nothin’ But Car ReviewsYouTube · Jun 8, 2025
Performance and handling
- Horsepower and torque: The engine produces 470 horsepower and a massive 975 lb-ft of torque, providing incredible pulling power for towing and hauling heavy loads.
- Transmission: It is paired with the robust Allison 10-speed automatic transmission, which provides smooth and seamless shifting.
- Towing: The diesel engine handles heavy trailers with ease, making it a capable workhorse for demanding tasks.
- Ride: The trucks equipped with this engine offer a smooth and stable ride, even when towing. Reviews often mention it has a more car-like feel on the highway compared to other trucks.
- Fuel efficiency: Some testing indicates the diesel engine can be more fuel-efficient than expected, potentially achieving over 20 MPG on a highway-heavy test loop.
You can watch this video to learn more about the 2025 Chevrolet Silverado 2500 HD diesel truck: 55sW.T.F Car ReviewsYouTube · Sep 7, 2024
Potential drawbacks and considerations
- Maintenance: Modern diesel engines require diligent maintenance. It is important to follow the recommended service schedule.
- Electronics and features: Some owners have reported issues with the truck's electronics, such as malfunctioning infotainment systems, connectivity problems (like CarPlay and Bluetooth), and false trailer connection alerts.
- Emissions and regeneration: At least one owner reported that the new Duramax regenerated more frequently in the first couple of months than their previous model, which is a normal process but can be noticeable.
- Seat comfort: Some reviewers have noted that the front seats can be uncomfortable on long drives.
This video discusses potential issues with the 2025 Duramax models: 54sThe Fast Lane TruckYouTube · May 22, 2025
What engine is in the 3500HD Duramax?
The 6.6L Duramax is the only choice for drivers and commercial operators who need the absolute maximum towing capacity. Recently updated, this engine produces an earth-moving **975 lb-ft of torque**, giving the 3500 HD the capability to pull up to **36,000 lbs** when properly equipped (DRW, Gooseneck).
What engine does a Silverado 3500 have?
6.6L V8 gas engine
The standard engine on the Silverado 3500 is a 6.6L V8 gas engine. This engine has a 3.73 rear axle ratio and capless fuel fill. The 6.6L V8 gas engine offers 401 horsepower at 5200 rpm, 464 lb.
