GM Gives Its 2027 HD Trucks Smarter Steering, Braking And Off-Road Tech

The 2027 Chevrolet Silverado HD and GMC Sierra HD are arriving with more than a fresh round of powertrain updates. General Motors has also made substantial changes to the way its heavy-duty trucks steer, stop, tow, and react when the pavement ends.

GM has reworked the steering system, introduced electronic brake boost, revised the chassis calibration, expanded the drive-mode strategy, and added a new Terrain Mode to ZR2 and AT4X models. The goal is to make these massive trucks feel more precise and predictable whether they are crawling through technical terrain, maneuvering a trailer into camp, or descending a steep grade.

“For 2027, we took GM’s proven HD validation playbook and turned up the capability — integrating new powertrain, braking, steering and chassis technologies for serious customers who push their trucks hard every day,” said Mark Dickens, Executive Chief Engineer for GM Full Size Trucks and SUVs. “HD customers don’t hold back — and neither did we.”

Electric Steering Changes The Feel

One of the most significant updates is the move to rack-and-pinion Electric Power Steering. GM calls it a segment first for heavy-duty pickups, and it replaces the previous hydraulic-assisted steering system with hardware designed specifically for HD applications.

The new system delivers approximately 30 percent more steering power than the outgoing hydraulic setup. That should be particularly useful during low-speed maneuvering, when negotiating tight trails, working around campsites, or handling the additional weight that can come with accessories and heavy front-axle loads.

More important from an off-road perspective, the electric system allows GM to tune steering behavior around different drive modes. The company says the setup improves on-center feel while reducing kickback through the steering wheel on rough roads and trails.

Because the system no longer relies on a hydraulic pump, hoses, or fluid, steering assist also remains independent of engine speed and brake-assist demand. That can provide more consistent steering effort when creeping through technical terrain or maneuvering at very low speeds.

More Brake Hardware And Smarter Control

Stopping a heavy-duty truck loaded with gear is one thing. Controlling that same truck while towing down a steep mountain road or easing over an obstacle is another.

For 2027, GM is introducing a segment-first electronic brake-boost system for its HD trucks. The system works with larger 14.6-inch front rotors, four-piston fixed front calipers, and upgraded rear brake hardware.

GM says the changes improve thermal capacity, pedal stiffness, and overall braking consistency. Pedal travel has also been reduced, with revised pedal positioning and calibration intended to create a more linear and predictable response.

Electronic brake boost also allows the braking system to work more closely with other vehicle systems. That becomes especially important as the truck’s drive modes increasingly coordinate braking, steering, stability control, and powertrain behavior rather than treating them as separate systems.

Terrain Mode Comes To The HD ZR2 And AT4X

That integration is particularly noticeable in the revised drive-mode lineup.

Tow/Haul mode now alters engine mapping, transmission behavior, exhaust braking, grade braking, Electric Power Steering assist, and electronic brake-boost tuning. Off-Road mode adjusts ABS, traction control, and stability control to permit additional wheel slip and side slip on loose terrain while also changing steering and brake response to reduce harsh feedback.

The biggest addition for off-road use, however, is the new Terrain Mode available on Silverado HD ZR2 and Sierra HD AT4X models.

This is the first time GM has offered the feature on its HD pickups. Terrain Mode works in both 4HI and 4LO and provides one-pedal off-road driving. Lift off the accelerator and the truck automatically applies braking, allowing the driver to control speed with the accelerator pedal alone.

That kind of control can be useful on steep descents, rocky climbs, and technical obstacles where maintaining an extremely slow, consistent pace is more important than outright speed.

Heavy-Duty Towing Still Matters

Of course, HD trucks still live and die by what they can pull.

For 2027, properly equipped Silverado HD and Sierra HD models are rated for up to 38,000 pounds of maximum trailering and a GCWR of as much as 46,500 pounds. GM says the revised chassis, suspension, steering, and braking systems were tuned together to improve stability and predictability when the truck is working near those limits.

Up to 14 available camera views help with hitching, backing, lane changes, and trailer monitoring. Available systems include Transparent Trailer View, Bed View, Surround Vision, Trailer Side Blind Zone Alert, and trailer tire-pressure and temperature monitoring.

The Gas V8 Gets More Muscle, Too

While GM’s new 8.3-liter Duramax diesel is getting most of the attention, the standard 6.6-liter gasoline V8 receives meaningful updates of its own.

Output rises to 412 horsepower and 472 lb-ft of torque, with GM claiming best-in-class standard torque among 2027-model-year HD gasoline engines. Updates include a new Turbo-Jet intake manifold, revised lubrication system, engine-mounted oil cooler, and digital oil-level display.

The gas V8 remains paired with the Allison 10-speed automatic transmission, with revised shift logic intended to keep the engine in a more useful portion of its powerband while accelerating, climbing grades, or managing heavy trailers.

The new Duramax is available for buyers who need maximum diesel capability, but the broader story surrounding the 2027 Silverado HD and Sierra HD is how much work GM has put into everything around the engine.

For the ZR2 and AT4X in particular, electric steering, stronger brakes, revised chassis controls, and the addition of Terrain Mode could have a meaningful effect on how these enormous trucks behave off pavement. An HD pickup will never shrink around the driver, but for 2027, GM appears intent on making its biggest trucks easier to place, easier to control, and more adaptable when the trail gets rough.