Brand New, Through and Through: Four Highlights of the 2027 GMC Sierra 2500 HD

The new GMC Sierra 2500 HD marks a major upgrade for the full-size pickup. Some brands might opt for subtle changes, new equipment packages, and novel trims, but the 2027 Sierra 2500 HD represents a broader technological shift as GMC embraces an entirely new way of designing a heavy-duty truck. Rather than simply refining the established formula, GMC has used the redesign to showcase just what’s possible in today’s 3/4-ton segment.

From its upgraded base engine and steering system to a new brake setup and a hulking 8.3L turbo-diesel that sets a new displacement record, GMC is giving drivers four compelling reasons to consider a new GMC Sierra 2500 for sale when they’re in the market for a new pickup. Let’s take a closer look at some of these changes and learn how the 2027 GMC Sierra 2500 HD embraces the latest in truck technology while honoring its long history of heavy-duty performance.

New 8.3L Duramax Turbo-Diesel

Progress tends to come in fits and starts, but don’t tell that to the GMC Sierra. While a 6.6L to 6.7L diesel engine had been the norm in the heavy-duty truck segment, the new Sierra 2500 HD 2500 HD makes a major leap in terms of displacement with an available 8.3L Duramax turbo-diesel V8 that’s certainly not short on superlatives. The new Duramax design isn’t just the biggest in the 3/4-ton segment. It’s the largest diesel ever fitted to a mass-produced pickup in the history of the U.S. auto industry.

Automakers have been content to squeeze more power from existing designs by using turbocharging, fuel injection, and other performance-enhancing techniques. The 2027 Sierra 2500 HD leverages all of the same cutting-edge components, but the turbo-diesel’s sheer size sets GMC’s heavy-duty truck apart.

The 8.3L engine produces 555 hp and 1,230 lb-ft of torque, which marks a substantial improvement over its 6.6L predecessor, which produced 470 hp and 975 lb-ft. of torque. While the truck’s towing stats remain unchanged, the Sierra 2500 HD remains one of the most industrious offerings in the heavy-duty segment, with the ability to tow 22,390 lbs and haul 3,850 lbs of payload.

The new Duramax engine isn’t just a standout for power. It also signals a promising new approach from GMC. It’s the first time that GMC has designed, developed, and built a new heavy-duty diesel V8 entirely in-house. That means the 8.3L turbo-diesel is specifically geared to the unique needs of today’s heavy-duty pickup drivers.

Updated 6.6L Gas V8

The new Duramax turbo-diesel hogs most of the headlines when it comes to the 2027 GMC Sierra 2500 HD for good reason, but the brand has also been quietly improving its base engine over the last year. The HD pickup’s 6.6L V8 hasn’t experienced the same growth spurt as the Duramax engine, but a bit of clever engineering sees the new entry-level engine climb the charts to become one of the segment’s more powerful offerings.

The 6.6L V8 routes its power through the same Allison ten-speed as the outgoing model, but GMC has tweaked the transmission’s shift logic to ensure the engine remains in its optimal operating range during heavy-duty tasks such as towing or climbing a steep grade. A new Turbo-Jet intake manifold improves efficiency and low-end torque, while an engine-mounted oil cooler and an updated lubrication system help keep things from getting too heated under the hood.

While the 2026 model was limited to 401 hp and 464 lb-ft of torque, the new base engine puts a bit more pep in the pickup’s step, with 412 hp and a class-leading 472 lb-ft of torque. The Silverado 2500 HD offers identical numbers, but the new engine gives the Sierra 2500 HD a significant advantage over relatively underpowered rivals like the Ram 2500, which makes 405 hp and 429 lb-ft of torque.

New Rack and Pinion Electric Power Steering System

The 2027 model marks another first for the Sierra 2500 HD, as the segment’s first rack-and-pinion electric power steering (EPS) system enters the fray. Previous models relied on a hydraulic-assisted steering system, but GMC says the new design will offer 30% more steering-assist power while better complementing the truck’s driver-assistance and trailering functions. It’s a substantial upgrade, but what does it actually mean, and how does it improve on the older hydraulic-assisted steering system?

Hydraulic Steering vs Electronic Rack-and-Pinion

Hydraulic Steering: This approach uses an engine-driven pump and hydraulic steering fluid to amplify a vehicle’s steering torque. The system draws power from the engine via the serpentine belt and even draws power when driving in a straight line. It requires regular fluid checks and is susceptible to wear and tear, though some drivers appreciate the real-time feedback hydraulic steering can provide.

Electronic Rack-and-Pinion: Instead of relying on pumps, hoses, and hydraulic fluid, the Sierra 2500 HD EPS is built around an electric motor and sensors that are controlled by an onboard computer. The on-demand system doesn’t draw electrical power unless it’s in use, and is largely maintenance-free aside from the rare sensor replacement. This delivers a more precise driving experience, as a rack-mounted EPS system can quickly react to digital inputs and dynamically adjust its ratio and weight based on vehicle speed.

The result is an easier, more responsive driving experience that provides increased low-speed turning power while reducing kickback and improving on-center precision. The new EPS is well-suited to the heavy-duty Sierra 2500 HD, especially for towing and off-road excursions.

New eBoost Braking

The 2027 Sierra HD certainly isn’t hurting for power, but the truck’s new-and-improved engines also create a bit of an issue when it comes time to pump the brakes. A standard set of brakes might struggle to keep the 555-hp Duramax turbo-diesel in check, but GMC has you covered with a new eBoost braking system. The segment-first feature combines a large set of front brakes with enhanced braking mechanics to dramatically improve the truck’s stopping power by as much as 20%, resulting in:

• Improved brake response
• Better downhill control
• Seamless integration with advanced driver assistance systems (ADAS)

The new braking system is about as comprehensive as they come, and includes larger brakes, four-piston front calipers, 14.6-inch front rotors, and revised rear brake hardware. That said, the clear highlight would have to be the new electronically controlled brake-booster system. Branded as eBoost, the system uses sensors, an electric motor, and an actuator to deliver precise braking pressure.

This replaces the old hydraulic brake-assist setup found on the outgoing model. It provides drivers with more control over braking, which is sure to prove useful when descending a hill with a heavy load. The eBoost system works in tandem with the ABS, traction control, stability control, transmission, and other key systems to improve braking power and pedal feel.

Experience the Latest in Heavy-Duty Trucks at McCluskey Buick GMC

We’ve covered some of the clear highlights of the latest model. While the new engines, steering, and braking systems are tough to ignore, they aren’t the only reasons to check out the new 2027 GMC Sierra 2500 HD. The 3/4-ton pickup also makes notable upgrades to the off-road-ready AT4X trim, adding a host of new equipment and a fresh Terrain Mode setting designed for low-speed, torque-rich applications like rock crawling.

While it’s made some important performance improvements, GMC hasn’t neglected the premium comfort and infotainment tech that’s long made the Sierra 2500 HD one of the market’s more refined pickups. From its 16-way power-adjustable front seats with built-in massage function to its 12-speaker Bose Premium Series audio system and available 15-inch head-up display, you’ll also be riding right on the cutting edge when you choose the Sierra 2500 HD.

McCluskey Buick GMC is here to help Cincinnati-area drivers enjoy the latest in heavy-duty pickup technology. From the latest 2027 Sierra 2500 HD to pre-owned models that are still ready to power through a full week of towing and hauling tasks, you’ll never be lacking in options when you bring us your business. Stop by today and learn how the newest Sierra 2500 HD is putting the rest of the 3/4-ton segment on notice.