2027 Silverado HD: New 8.3L Duramax V8 Revealed

GM is raising the capability of its 2027 heavy-duty pickups with a new 8.3-liter Duramax V8, electric steering, electronic braking and up to 38,000 pounds of gooseneck towing.

GM introduces a new era for its HD pickups

General Motors is giving the 2027 Chevrolet Silverado HD and GMC Sierra HD a major technical update.

The biggest change is under the hood. GM has introduced an all-new 8.3-liter Duramax Turbo-Diesel V8 designed specifically for its heavy-duty pickup trucks.

The engine produces 555 horsepower and 1,230 lb-ft of torque. GM identifies those figures as best-in-class diesel output.

The new powertrain is also part of a wider redesign.

GM has updated the steering, braking and drive-mode systems. The goal is to make the trucks easier to control while towing, hauling and driving off-road.

The 2027 GMC Sierra combines the new Duramax V8 with upgraded towing, steering and braking technology.

GM says the new diesel is its first clean-sheet HD V8 designed, developed and manufactured in-house for heavy-duty pickup applications.

The engine uses a compacted graphite iron block, a forged crankshaft, forged connecting rods and steel pistons. These components were designed around the sustained loads expected during heavy-duty use.

The engine also gets a variable-geometry turbocharger and a compact dual-stage air-to-water charge-cooling system.

GM has also redesigned the cooling strategy and combustion system. The company says those changes are intended to improve refinement while maintaining consistent performance under heavy loads.

The Duramax is paired with an Allison 10-speed

The new 8.3-liter diesel works with an Allison 10L1000 10-speed automatic transmission.

GM has also updated the shift logic to keep the engine in its most useful operating range. An upgraded exhaust-braking system is part of the package as well.

The combination is designed for customers who spend long periods towing.

GM says the new engine can provide stronger acceleration when launching heavy trailers. It is also designed to maintain power while climbing grades and improve control while carrying a heavy load.

The 2027 Chevrolet Silverado HD receives the same new Duramax 8.3L diesel and chassis technology as the GMC Sierra HD.

The gasoline engine also receives an update.

The 6.6-liter gas V8 now produces 412 horsepower and 472 lb-ft of torque. GM says the engine gets a new intake manifold, revised lubrication hardware, an engine-mounted oil cooler and a digital oil-level display.
Both engines use the same Allison 10-speed transmission.

That gives the 2027 HD lineup two different approaches. Buyers can choose the high-torque diesel or the updated gasoline V8.

Electric steering replaces the hydraulic system

One of the less visible changes could have a major impact on everyday driving.

GM has introduced rack-and-pinion electric power steering to its heavy-duty pickups. The company describes it as a segment-first system for HD trucks.

The new system provides roughly 30% more steering output than the previous hydraulic system.

It can also be tuned through the truck’s drive modes. GM says it improves on-center feel, reduces steering kickback and operates more quietly than the previous setup.

The move to electric steering also removes the hydraulic pump, hoses and fluid used by the previous architecture.

That simplifies the system while giving engineers more control over steering assistance.

Electronic braking adds more control

The 2027 Silverado HD and Sierra HD also receive a new electronic brake-boost system.

GM describes it as the first electronic braking architecture in a heavy-duty pickup in the segment. The trucks also receive larger 14.6-inch front rotors and four-piston fixed front calipers.

The new system is designed to provide a more consistent pedal feel.

It also supports faster integration with driver-assistance systems such as adaptive cruise control and automatic emergency braking.

That matters when towing a large trailer.

More consistent braking can help make repeated stops and downhill sections easier to manage, especially when the truck is operating close to its limits.

The new Duramax 8.3L V8 is assembled at GM’s DMAX operation in Ohio.

Up to 38,000 pounds of gooseneck towing

Towing remains one of the central goals of the redesign.

GM says properly equipped 2027 Silverado HD and Sierra HD models can tow up to 20,000 pounds with a conventional trailer. The maximum rises to 38,000 pounds with a gooseneck trailer.

That 38,000-pound figure is available on specific configurations.

GM also says every diesel dual-rear-wheel model will be capable of towing 30,000 pounds or more, depending on configuration.

The trucks also receive new camera technology.

Up to 14 available camera views can help with hitching, reversing, trailer monitoring and lane changes. The system can include Transparent Trailer View, Bed View and Surround Vision.

New Terrain Mode targets off-road driving

GM is also changing the way its off-road HD trucks operate.

The ZR2 and AT4X can receive a new Terrain Mode. It enables one-pedal off-road driving in 4HI and 4LO.

When the driver lifts off the accelerator, the system automatically applies braking.

That can make low-speed driving easier on steep grades and technical terrain. The steering, braking and powertrain systems work together to provide a more controlled response.

A major powertrain statement from GM

The 2027 heavy-duty trucks are therefore changing in several areas at once.

The new 8.3L Duramax V8 brings 555 horsepower and 1,230 lb-ft of torque. The gas V8 gains output, while electric steering and electronic braking introduce new hardware to the HD segment.

The new diesel will be built at GM’s expanded DMAX facility in Brookville, Ohio. GM previously invested $920 million to support the engine program.

The first 2027 Chevrolet Silverado HD and GMC Sierra HD trucks are expected to arrive at U.S. dealerships later this year.

For the American heavy-duty market, GM’s new formula centers on one major number: 1,230 lb-ft of torque, supported by redesigned steering, braking and towing systems engineered around the same goal: giving the new HD trucks more capability and control.