Any Time We're Offered the chance to jump behind the wheel of a medium-duty truck, we don't hesitate. Typically weighing close to 8500 pounds or more, depending on how they're outfitted, these are the real work trucks of the commercial-duty world--the big boys. If you live anywhere near a city, you'd be hard-pressed not to drive by at least a dozen of these Chevy Kodiaks or GMC TopKicks in a day, some with cargo boxes in back, others perhaps with dump or stake beds.

The crew-cab C4500's base price is $34,086, but ours came equipped with the Duramax turbo-diesel and Allison transmission (and a host of other options) and lists for $48,678. The two-wheel-drive crew cab C4500 came fully decked from the GM factory, with quite a few specialty pieces from truck upfitter Monroe Truck Equipment, which works with the platforms as soon as they come off the line, installing performance, comfort, and/or style-enhancing option packages.

Our truck had the pickup bed (a standard one-ton dualie bed with a few modifications) with a 30,000-pound-rated pop-up gooseneck hitch hidden underneath. In addition, the truck had the Ultra Ride air suspension, which replaces the rear leaf springs with two frame-located airbags that greatly improve the empty ride of the truck and increase overall carrying capacity. We went out of our way to hit speed bumps in parking lots as well as the larger ones communities use to slow drivers down. The bumps weren't as punishing as you'd expect, especially since the truck also was equipped with fully air-suspended seats, offering a full six inches of shock-absorbing travel. Monroe also installed a separate cab air suspension, which includes two additional airbags under the cab, along with two shock absorbers. The result is a tame ride, even when empty, over rough roads--it rode considerably better than any one-ton dualie we've ever driven, and the ride should get even better with a few thousand pounds in the bed.

The heart of the Kodiak is the same Duramax 6600 and Allison six-speed transmission (with PTO) in Silverado and Sierra HD trucks, and although some versions of the Duramax can be tuned to 350 horsepower and 650 pound-feet of torque, the medium-duty versions are not. Our Kodiak numbers are 300 horses and 605 pound-feet. During runs around town, we were most impressed with how smoothly the Allison shifted and ran through the gears. You'd think a powertrain designed to carry and haul in excess of 20,000 pounds would shift abruptly when empty, but that wasn't the case. The new software is better able to detect what types of loads exist and makes more seamless adjustments to the shift pattern. The gearbox holds gears longer than many of the transmissions tuned for maximum fuel economy.

Inside, Monroe replaced the front seats with two air-suspended fully bolstered leather captain's chairs with a solid-oak center console. In back, the three-passenger leather bench seat is electronically controlled and reclines (and folds flat) at the touch of a button. With the seats laid flat, the rear area is converted into a bed large enough for two children to stretch out and sleep, or two adults could cozy up back there. A big-screen DVD player and a six-disc CD audio system and speaker upgrade are also available.