First details of GM’s new 8.3-liter Duramax engine

Badging for the new 8.3L Duramax TD V8 on the 2027 Chevrolet Silverado HD (Photo: GM)

General Motors has released first details about its all-new 8.3-liter V8 Duramax turbodiesel engine, which has been dubbed ‘Mongoose’.

The new engine will feature in the 2027 MY Chevrolet Silverado HD and GMC Sierra HD.

The new release breaks the recent line of 6.6-liter Duramax TD engines (470 hp, 1,322 Nm). Said to be the largest engine GM has ever fitted to a pickup, the new Duramax is even larger than the 8.1-liter Vortec petrol engine offered between 2001 and ‘06.

That greater displacement is reported to deliver up to 555 hp and 1,668 Nm of torque (1,230 lb ft).

Features include a lighter engine block made from compacted graphite iron. The crankshaft and connecting rods are both forged to save weight and improve part strength, while the pistons are made from steel. There is also a crankshaft isolation system to reduce NVH.

A variable-geometry turbo is paired with a dual-stage air-to-water intercooler for added power, while there is also an upgraded engine cooling system. The emissions aftertreatment hardware is said to have been designed for trucks which will have a hard working life.

Power is delivered to the wheels via a 10-speed Allison auto transmission. An electronic brake-boost architecture is said to improve the HD driving experience.

Maximum towing capacity is 20,000 lb, up to 38,000 lb gooseneck on equipped vehicles.

It was reported that GM spent in excess of $900 million across development of the new Duramax model. The engine will be produced at the GM DMAX complex in Brookville, Ohio.

According to General Motors, more than 60% of heavy-duty customers select a diesel engine for their new vehicles.