GM Teases “Mongoose” Duramax Diesel Set for Chevrolet Silverado HD, GMC Sierra HD

• GM confirms an all-new 8.3L Duramax turbo-diesel V8 for its refreshed 2027 heavy-duty pickups.

• Chevrolet Silverado HD and GMC Sierra HD will both be available with the new diesel engine.

• Horsepower, torque, and towing ratings have not yet been announced.

General Motors has shared a first official look at a new generation of its heavy-duty diesel powertrain, confirming an all-new 8.3L Duramax turbo-diesel V8 for its refreshed 2027 pickup trucks.

GM has not yet released horsepower, torque, towing ratings, or other detailed specifications; however, we expect the numbers to be class-leading in most regards. No one will be surprised by a 1,000+ lb-ft torque rating.

The increase to 8.3 litres represents a notable upgrade for GM’s heavy-duty diesel lineup. Current Silverado HD and Sierra HD diesel models use a 6.6L Duramax V8. And with such a considerable bump in displacement, more power is inevitable.

GM is referring to the new engine as the “Mongoose,” a name that also serves as a competitive reference. In its teaser, the automaker points to a rival heavy-duty V8 diesel known as the “Scorpion,” a name associated with Ford’s Power Stroke diesel program.

The teaser shows that GM will emphasize power and capability when it fully details the new engine. The current 6.6L delivers 470 hp and 975 lb-ft of torque. We’ll wager a starting output of 500 hp and 1,100 torques.

2027 Chevrolet Silverado HD, GMC Sierra HD Getting New Engines

The powertrain announcement also provides an early indication of what is coming for GM’s next round of heavy-duty truck updates. Both the Chevrolet Silverado HD and GMC Sierra HD are scheduled to receive refreshes for the 2027 model year, but not a full ground-up revamp like the 1500 trucks.

Chevrolet and GMC will provide additional information on the refreshed Silverado HD and Sierra HD, including specifications for the 8.3L Duramax, in future announcements.