What is new on the 2027 heavy-duty trucks
- Models
- 2027 Chevrolet Silverado HD and GMC Sierra HD
- Diesel
- All-new Duramax 8.3L Turbo-Diesel V8
- Gas
- Enhanced 6.6L V8, standard
- Transmission
- Allison 10-speed 10L1000
- On sale
- Launching this year
GM's 2027 heavy-duty lineup arrives this year across the Chevrolet Silverado HD and GMC Sierra HD, and the headline change is an all-new Duramax 8.3L Turbo-Diesel V8 (opens in a new tab). GM describes it as its first clean-sheet HD V8 designed, developed and manufactured internally for heavy-duty pickups.
GM rates the diesel at 555 hp, with torque reaching 1,230 lb.-ft. Notable hardware includes steel pistons and a variable-geometry turbocharger. GM also describes improvements to exhaust braking and a revised aftertreatment arrangement.
The standard engine is an enhanced 6.6L gas V8 rated at 412 hp and 472 lb.-ft. of torque. It gains a new Turbo-Jet intake manifold, a revised lubrication system with an engine-mounted oil cooler and a digital oil-level display, and it is assembled at the Tonawanda Engine Plant in New York. Both engines pair with the Allison 10-speed 10L1000 transmission.
GM says it will manufacture the diesel at its expanded DMAX facility in Brookville, Ohio, a 1.4-million-square-foot plant that handles machining and assembly under one roof. The company previously invested $920 million in the DMAX expansion. More than 60 percent of heavy-duty customers choose diesel, and GM brands hold the majority of diesel share in the segment, according to GM.
Steering, braking and off-road changes
The 2027 trucks add rack-and-pinion electric power steering, which GM calls a segment first for heavy-duty trucks. It replaces the previous hydraulic-assisted system and delivers approximately 30 percent more power than the hydraulic steering gear, according to GM. The design removes hydraulic pumps, hoses and fluid, includes built-in redundancy and provides full steering assist regardless of engine speed.
GM also adds an electronic brake-boost system, which it describes as a first for an HD pickup. The setup supports Adaptive Cruise Control and Automatic Emergency Braking, and its diagnostics can detect fade or leaks sooner, GM says. It eliminates the shared hydraulic source for steering and braking. The front brakes use 14.6-inch rotors with four-piston fixed calipers.
An enhanced drive-mode strategy brings updated Tow/Haul and Off-Road calibrations. A new available Terrain Mode adds one-pedal off-road control, a first for GM HD trucks. GM showed the 2027 Chevrolet HD ZR2 off-road as a preproduction model.
How to get one
GM plans to launch both trucks this year. Buyers will have a diesel option, while the gas V8 remains standard.
The steering and brake changes make this update relevant to shoppers considering the standard gas engine, too.