General Motors has improved the Sierra 1500, with increased payload and towing capacities, plus a deeper bed. It also improved the powertrain, fuel economy and introduced several unique innovations on higher trims.
The biggest change is in the powertrain. Its 5.3-liter V8 engine, now paired with a new eight-speed automatic transmission, and the combination provides better throttle response and quicker acceleration, answering one of our chief criticisms of the dull, flat-footed previous generation. Combining this transmission with the loss of about 300 pounds help the Sierra (and the Chevrolet Silverado, which we tested) achieve 17 mpg overall, a 1-mpg gain over the previous truck. We also tested the diesel version mated to a 10-speed automatic which yielded 23 mpg overall.