Quick Facts:
- Trucks: 2027 Chevrolet Silverado HD ZR2 and GMC Sierra HD AT4X.
- New feature: Terrain Mode with one pedal driving in 4HI and 4LO, a first for GM heavy-duty trucks.
- Steering: Rack-and-pinion electric power steering replaces hydraulic assist.
- Brakes: Electronic brake boost, 14.6-inch front rotors, four-piston fixed front calipers.
- Towing: Lineup maximum is 38,000 pounds gooseneck, on a properly equipped 3500 HD 2WD dually.
- Arrival: Expected at US dealers beginning late 2026.
- Price: Not announced. GM says MSRP comes in a future update.
- Best for: Heavy-duty owners who tow all week and drive trails on weekends.
 6 min read
In This Article
2027 Silverado HD ZR2 Overview: What GM Added
The 2027 Silverado HD ZR2 and Sierra HD AT4X gain a feature no GM heavy-duty truck has offered before. Terrain Mode brings one pedal driving to 4HI and 4LO, so lifting off the accelerator applies the brakes for you. GM announced it on September 24, alongside a new diesel.
The engine got most of the headlines. However, the chassis changes matter more once the pavement ends. Every 2027 heavy-duty truck moves to rack-and-pinion electric power steering and a new electronic brake boost system. GM also calls both segment firsts. Because the ZR2 and AT4X also get Terrain Mode, they gain the most off pavement. For the engine side, read our reports on the L5P Duramax retirement and the 8.3L Duramax GM confirmed.
Notably, GM’s September 24 release leaves several answers open. For example, the release lists no price, no curb weights, and no engine chart by trim. GM expects the trucks at dealers late this year. This guide covers what is confirmed, what to ask a dealer, and what to pack for your first trip.
One pedal driving handles the descent, but it does not free a stuck truck. Heavy trucks need rated recovery gear, and it belongs first on your packing list. Start with a Yankum Rattler 1-inch kinetic recovery rope, listed at 33,500 pounds breaking strength. Add a Factor 55 Extreme Duty soft shackle. Also, Nilight 3/4-inch D-ring shackles carry a listed capacity of 9,500 pounds.
Recovery gear for a heavy truck
Nilight 2 Pack 3/4" D-Ring Shackle 4.75 Ton (9500 Lbs) Capacity wit…
Key Facts at a Glance
With the gear covered, here is what GM and its brand pages have confirmed so far.
| Item | Details |
|---|---|
| Terrain Mode | ZR2 and AT4X only. Lifting off the accelerator applies the brakes in 4HI and 4LO. |
| Steering | Rack-and-pinion, about 30% more power than the old hydraulic gear. |
| Brakes | Electronic brake boost, 14.6-inch front rotors, four-piston fixed front calipers. |
| ZR2 hardware | 1.5-inch factory lift, larger Multimatic DSSV dampers, rear e-locker, 35-inch mud-terrain tires, aluminum skid plates. |
| AT4X hardware | Larger DSSV dampers than last year and a lifted suspension. |
| Towing | Lineup maximums of 20,000 pounds conventional and 38,000 pounds gooseneck, when properly equipped. |
| Arrival and price | Late 2026 at US dealers. MSRP not announced. |
How Terrain Mode Works Off Pavement
Terrain Mode joins Normal, Tow/Haul, and Off-Road in the drive mode list. It works in both 4HI and 4LO. When you lift off the accelerator, the truck applies the brakes on its own. As a result, GM says the driver gets precise control on steep grades and technical obstacles.
Off-Road mode already loosens ABS, traction control, and stability control to allow more wheel slip and side slip on loose surfaces. Steering and brake tuning also cut harsh feedback in this mode. GM lists Terrain Mode as its own mode. It adds automatic braking when you lift off the accelerator.
I drive a 2025 Chevy Colorado ZR2, so a ZR2 badge on a heavy-duty truck gets my attention. However, GM has not said how hard the truck brakes when you lift, or how it behaves on a wet ledge. Those details also decide whether it beats hill descent control. For comparison, see our guide to how hill descent control works.
Silverado HD ZR2 Steering, Brakes, and Trail Hardware
Terrain Mode is only part of the chassis story. The steering change is the biggest mechanical shift, and it reaches every 2027 heavy-duty truck. Electric power steering replaces the old hydraulic system and brings about 30% more power. It also removes the pump, hoses, and fluid. GM says electric steering gives full assist regardless of engine speed or brake assist use. The new rack also cuts kickback on rough roads and trails, according to GM.
Brakes change as well. The new electronic brake boost also pairs with 14.6-inch front rotors, four-piston fixed front calipers, and upgraded rear hardware. According to GM, pedal travel is shorter and the pedal feel is more linear. Braking also no longer shares a hydraulic source with steering, which GM says removes weight and complexity.
Chevrolet’s page adds hardware for the HD ZR2: a 1.5-inch factory lift, larger Multimatic DSSV dampers, and a rear e-locker. It also lists aluminum skid plates and 35-inch mud-terrain tires. GMC’s page names larger DSSV dampers than last year and a lifted suspension for the AT4X.
The ZR2’s 35-inch tires make airing down routine on the trail. First, an ARB E-Z Deflator kit handles the air-down. Then a VIAIR 450P compressor, listed for tires up to 42 inches, restores the pressure. Finally, an ARB Speedy Seal 2 kit covers a trail puncture.
Air down and air up for 35-inch tires
ARB ARB505 Deflator Kit 10-60 PSI Tire Pressure Gauge Rapid Air Dow…
What This Means for You
Gear is the easy part. GM has not announced a price for these trucks. It says MSRP comes in a future update, and it expects the trucks at dealers late in 2026. If you plan to buy, wait for the window sticker before you commit to a deposit.
Ram is a direct rival. According to our July report, the 2027 Ram Power Wagon diesel rides on 33-inch tires and drops the front winch. The HD ZR2 answers with 35-inch tires from the factory, so tire size is one difference to weigh.
One item deserves a watch. In August, NHTSA opened an engineering analysis of GM’s eBoost brake system. Its problem description reads “failure of eBoost system causing loss of braking and steering assist functions,” an allegation on file, not a finding. Our report on the NHTSA GM eBoost brake investigation has the details. The analysis covers 2023 through 2026 Colorado and Canyon trucks, so my 2025 Colorado ZR2 sits inside it. However, the filing does not name the Silverado or Sierra. Since GM also uses the eBoost name on the new HD brakes, ask your dealer whether the two share hardware.
Final Thoughts
For me, the steering and brake work is the story here, which is why the eBoost question matters. Terrain Mode is the bonus. A truck this size is easier to place when the steering is precise and the pedal feels linear.
The catch for now is how much is unknown. GM has not shared price or curb weights, and it has not said how Terrain Mode feels in the dirt. If you need a truck this fall, a leftover 2026 is still an option.
Wait for first drive reports and the window sticker. Then compare the Silverado HD ZR2 with its GMC twin and the Power Wagon before you sign. In the meantime, build your recovery kit and tire tools, because they carry over to whatever truck you buy.
Frequently Asked Questions
What is Terrain Mode on the 2027 Silverado HD ZR2?
Terrain Mode is a new drive mode for the ZR2 and AT4X. It works in 4HI and 4LO and applies the brakes when you lift off the accelerator, so you control speed with one pedal.
Does the Sierra HD AT4X also get one pedal driving?
Yes. GM lists Terrain Mode for both the Silverado HD ZR2 and the Sierra HD AT4X. It is the first time GM has offered the feature on its heavy-duty trucks.
How much will the 2027 Silverado HD ZR2 cost?
GM has not announced pricing. The company says MSRP and more product details come in a future update.
When does the Silverado HD ZR2 reach dealers?
GM expects the 2027 Silverado HD and Sierra HD at US dealers beginning late 2026.