The transmission is a big part of the driving experience and has the characteristics that have made the Allison famous. Shifts are crisp, and the gearing seems optimal for driving country roads or city streets. The manual mode lets you pull the shifter down to "M" so you can control the gears with buttons on the stalk, and unlike some manu-matic transmissions, the Allison will hold the gear you choose until redline is hit and fueling is cut off; it won't upshift until you say so. You can also pull the lever down to "1" at any speed, and the transmission will be put in the lowest gear that won't spin the engine past redline. This is great for highway off-ramps and other situations where full stopping power is necessary. While in Tow/Haul mode, the transmission senses when the brakes are tapped and engages the torque-converter clutch to use the drivetrain drag to help slow the truck.
 Exhaust that doesn't get regurgitated...  Exhaust that doesn't get regurgitated into the intake spins the turbo and is then fed through a 4-inch pipe into an oxidation catalyst before it travels to the diesel particulate filter. |  The exhaust is then sent into...  The exhaust is then sent into the ceramic honeycomb inside the large diesel particulate filter. Soot is trapped and builds up until backpressure sensors tell the engine it's time to go into regeneration mode... |  ...That's when the computer...  ...That's when the computer triggers post-combustion fuel injections that raise the exhaust temperature and burn off trapped soot. |
For the first time, GM is offering an integrated trailer-brake controller-something Blue Oval fans have been using to win garage debates across the country during the past few years. The controls are mounted below the steering wheel, and there is a readout in the gauge cluster to help keep your eyes on the road.
There are two main interior offerings: the Pure American Pickup (with big grab handles, an extra glovebox, and simple styling) and Luxury-Inspired (similar to the plush interiors in the SUVs). Both use upgraded materials and parts supplied from vendors who apparently worked together this time because the A/C buttons, radio, 4WD knob, and other controls actually match. There's lots of storage space in the center console, and the seats are large and comfortable like GM customers are used to. The new body is much quieter, thanks to sound-deadening and stiffening. Squeaks and rattles are not a problem, and noise (from wind and the quieter Duramax) is minimal.
 Dualie trucks now have sheetmetal...  Dualie trucks now have sheetmetal rear fenders (instead of plastic) because of a hydroforming process that uses high-pressure water to precisely bend the metal. |  We weren't sure about the...  We weren't sure about the look of the dualie wheelwells or the exhaust tip when we first saw photos, but they look much better in person. |  The rear seats in the Extended...  The rear seats in the Extended Cab and Crew Cab fold up flat against the seatbacks for storage space. |
Driving the new trucks is an experience that's exactly what you'd expect from the next-generation GM trucks-and that's a good thing. The pickups have undergone numerous upgrades from the old GMT-800 platform, but the changes are all improvements, and the trucks immediately feel familiar to someone who is already inclined to shop for a Chevy or GMC. The new 2500HD and 3500HD with the Duramax LMM clean-diesel engine are very strong, they are backed by a great transmission, and the body and interior are on the same level as the other 3/4- and 1-ton trucks on the market. We'd call it a home run, but we'll wait until we get one on a dyno and a dragstrip.