Three engines all have aluminum cylinder blocks and direct fuel injection that makes big difference to power and fuel economy; six-speed automatic transmissions for bottom and middle trims, but new eight-speed auto standard with the 6.2-liter V8; V6 makes nearly 300 horsepower and is standard for every cab style and two- /four-wheel-drive.
Although perhaps not quite the dramatic makeover that some General Motors fans expected, the Sierra/Silverado full-size pickups have nonetheless gained plenty of respect. While Chevrolet positions the Silverado as a kind of middle-ground pickup for both work and play, in the Sierra’s case those virtues are distinctly separated. More basic GMC models accentuate the “Professional Grade” tag and the pitch is directed at buyers who rely on their pickups to earn a living. At the opposite end of the scale is the Sierra Denali sub-brand that places a much higher value on coddling content. In either case, the Sierra’s primary identification point can be spotted in your rearview mirror. The entire front end, including grille, headlights, bumper and in-your-face GMC logo, are more massive than before and in total make a bolder statement than the Silverado does. Some minor sheetmetal differences exist between the Chevy and the GMC, but that’s about it. Even the interiors of the two pickups share the same basic dash, control panel and available touch-screen communications center that are a masterstroke of efficient legibility. Of course as you scale the trim-level ladder the appointments become more luxurious and the cabin resembles something approaching a high-end limo, especially in the four-door crew-cab models. Improvements in aerodynamics, insulation and weather sealing help shut out intrusive noises. Just as a greater use of aluminum in fabricating various body panels and suspension parts has kept the Sierra’s weight in check, the three new engines also benefit. All use aluminum cylinder blocks and direct injection, whereby fuel is force-fed into the cylinders under high pressure. There’s also variable valve timing for improved low- and high-speed performance, while half the cylinders in V8 engines will automatically shut down in steady-state cruise conditions to save fuel. The V6 engine also runs on four cylinders in such situations. The base 4.3-liter V6 might have the same displacement as before, but now makes 285 horsepower and 305 pound-feet of torque. The old iron 4.3 was good for just 195/260 pound-feet. V8 choices consist of a new 5.3-liter unit with 355 horses and 383 pound-feet, up from 315/335, and a 6.2-liter piece rated at 420/450 pound-feet. The larger of the V8s now gets an eight-speed automatic transmission. It’s standard in the fancier Sierra Denali, not to mention a rather substantial list of content that includes unique 20-inch chrome and wood and leather innards, along with standard magnetic ride control for 2015.