2027 Chevy Silverado HD and GMC Sierra HD get an 8.3‑liter Duramax V‑8 and major chassis upgrades

# What changed for 2027 General Motors updated the Chevrolet Silverado HD and GMC Sierra HD for 2027 with a focus on heavier towing capability and improved on‑road control. The headline is a newly developed 8.3‑liter Duramax V‑8 diesel, nicknamed Mongoose, offered as an optional engine on both models. GM also revised the gasoline V‑8, updated steering hardware, and upgraded the braking system.

# Powertrains and what they mean The new Duramax 8.3‑liter V‑8 produces 555 horsepower and 1,230 pound‑feet of torque. GM positions this as the flagship diesel for its HD pickups. A revised 6.6‑liter gasoline V‑8 now makes 412 hp and 472 lb‑ft. Both engines pair with an Allison 10‑speed automatic transmission.

# Towing and payload figures GM raised towing limits across the lineup. Key published figures include:

• Up to 20,000 pounds with a conventional trailer hitch.
• Up to 38,000 pounds with a gooseneck hitch.
• Every diesel model with dual rear axles (dually) now has at least a 30,000‑pound towing rating.

These increases reflect the new engine outputs and strengthen GM's position in the heavy‑duty market where towing capacity is a primary buying factor.

# Steering and braking upgrades GM replaced the long‑standing recirculating‑ball steering used on its HD trucks with an electric rack‑and‑pinion system. GM states the new steering delivers about 30 percent more assist than the previous hydraulic arrangement. The expected effect is more precise and confident steering feel, particularly while towing.

On the stopping side, the trucks gain a first‑segment electronic brake‑boost system, larger 14.6‑inch front rotors, four‑piston front calipers, and revised rear braking hardware. Pedal placement and brake travel were adjusted for a more linear feel and better heat resistance under heavy use.

# Timing and market position GM says the updated Silverado HD and Sierra HD should arrive by the end of the year. Pricing has not been released. With these changes—especially the high‑torque 8.3‑liter diesel and improved chassis hardware—GM is positioning the refreshed trucks to compete on towing capability and driver confidence during heavy hauling tasks.

# Bottom line The 2027 HD updates concentrate on raw capability and control: a much larger diesel V‑8 for extreme torque, revised gas V‑8 hardware for durability, higher published tow limits, and tangible steering and brake improvements to make hauling heavy loads easier to manage on the road. Expect final specs and pricing closer to the on‑sale date later this year.