Repair-It

this truck-specific, 2.8-liter turbodiesel four generates 181 hp at 3,400 rpm, and 369 lb-ft of torque at 2,000. At least 330 lb-ft are available between 1,400 and 2,900 rpm.

How far has mainstream automotive technology come in 30 years? The last diesel offered in a small U.S. Chevy truck—the 1985 S-10—was built by Isuzu. At 2.2 liters, it made 62 hp and 96 lb-ft. The contemporary Ford Ranger offered a diesel through 1987. That was a 2.3-liter turbo from Mitsubishi, and it generated 86 hp and a whopping 134 lb-ft.

The stand-out bit of tech in the 2.8-liter Duramax might be its liquid-cooled, variable-geometry turbocharger, with a little electric motor that varies the diameter of the impellor. Once reserved for Freightliners and Porsche 911 Turbos, VGTs operate with minimal lag in single-turbo applications. They have a low boost threshold and are particularly efficient at higher engine speeds. In the 2.8L Duramax, the VGT generates up to 40 PSI of boost, but requires no waste gate.

The 2.8-liter Duramax was developed by GM Powertrain in Pontiac, Michigan, and Rüsselsheim, Germany. The basic design has been in production since 2011, primarily for small pickups sold in Southeast Asia and South America. Application in North America prompted another round of development and a second generation, focused on adaptation for climate extremes and better NVH control.

GM’s Hydramatic 6L50 automatic, the only transmission offered with the 2.8-liter Duramax, is also equipped with something GM Powertrain calls CPA--for centrifugal pendulum absorber. CPA is essentially an electronically managed, spring-actuated clutch in the torque convertor. It closes or releases in milliseconds to counter-balance quick variations in torque and minimize lash through the transmission, driveshaft and rear end.