Sometimes a marketing department's claim of "all-new" approaches the truth. That's the case with General Motors' Heavy Duty pickups and cab-chassis trucks, which were extensively upgraded and refined for the 2011 model year, even if GM doesn't call them all-new.

They went into production in June, when GM sponsored a ride-and-drive event, centered in western Maryland and featuring about a dozen iterations of the 2011-model Chevrolet Silverado HD and GMC Sierra HD trucks.

Over a day and a half I drove four trucks, starting with a no-frills GMC 3500HD cab-chassis with a steel flatbed, called a "ranch body" in the West. Our hosts assigned me to this shortly after touchdown at Baltimore-Washington International Airport.

Manning the shotgun seat was Mark Cieslak, GM's chief engineer for full-size trucks. He good-naturedly endured my comments about the company's vehicles and questions about its product plans. He said he appreciated the feedback about GM cars and trucks, and deftly fended off my future-tense queries.

I grilled him about reports that GM will return to Class 4 and 5, using pickup-based cabs like this truck's instead of the wider van-based cabins of the now-defunct C-series conventionals, and chassis from - what, Mark? "Yes, well, we're looking at a number of things," he said. I wondered if GM would downsize its powertrains, ala Mercedes-Benz Sprinter, to achieve better fuel economy. Cieslak said a Chevy or GMC can haul and tow much more than any Sprinter, but smaller engines are among a number of corporate considerations.

Well, what about the rough ride of this truck, then, even on smooth Interstate pavement? "You think it rides rough?" he said. Yes, I did, but of course there was no load on the bed, so the 3500HD's stiff springs weren't flexing much. And Regular Cabs like this don't get the new hydraulic rear mounts that are used on the longer Extended and Crew Cabs. Tie a couple thousand pounds of hay, lumber or cement bags onto the bed, and the ride would settle down just fine.

The heavy suspensions boosted the chassis skyward and put the cab's floor about 2 feet off the pavement. I'm a short guy with short legs and I struggled to get aboard, which led to my oft-repeated rant against GM: Why no grab handle at the driver's position?

But that's the total of my complaints about the new GM 2500 and 3500 HDs.

They are really nice to drive, and seem every bit as capable as competitors' trucks. This 3500 HD had the base W/T trim, but the bench seats were shaped like buckets and comfortably supportive. The gauge package was fairly complete and handsomely trimmed, while controls were easy to see and manipulate. With windows up the interior was quiet at freeway speeds. The Vortec 6000 gasoline V-8 was smooth and gutsy, and the Hydra-Matic 6L90 six-speed shifted almost imperceptively.

Exterior styling remains streamlined with chunky bulges over the wheel cutouts. There's gobs of chrome in the grille, and hoods have bulges suggesting lots of power and torque. Indeed, the gasoline and diesel engines used in the HDs have high ratings - 360 horsepower and 380 pounds-feet for the Vortec 6000 and 397 horsepower/765 pounds-feet for the Duramax.

Lost in a Crewcab

After arriving at our western Maryland resort, another editor and I got a fire-engine-red, Duramax-powered Crewcab pickup with an upscale interior that was hitched to a long horse trailer.

Our hosts had mapped a circuitous route using U.S. and state highways. We started on hilly, curvy highways in Maryland, then dipped into rural West Virginia on a sometimes narrow back road that meandered over tall hills and along steep ravines. At one point we met a county dump truck that forced the other editor, who was driving, far to the right, to where our trailer's right-side tires tripped off the pavement and onto inclined dirt. But as we edged past, the trailer tires followed us back onto the asphalt.

At a state park, I took over the driving. We backtracked down that county road, this time with steep slopes to our right and generally with more room to make switchback turns. I definitely had an easier time of it than my driving partner - or did until we got lost back in civilized Maryland. We missed a turn into a city park and rambled on, eventually stopping and calling up OnStar for help.

We got a combination of live voices and automated instructions that didn't always jibe with the real-life road layout. But we consulted our printed map, and, after stopping to ask folks in a general store for directions, we eventually we got to where we needed to be.

The GMC truck proved more than game through all the off-route wandering, and the horse trailer followed along like a pack mule. The Duramax was smooth and quiet, and it made absolutely no smoke or odor, just as EPA's 2010 exhaust regulations dictate. Like most '10-spec diesels, the Duramax uses a particulate filter to grab soot and urea injection on its exhaust to wipe out virtually all traces of nitrous oxide.

The Duramax's hefty torque requires the beefy Allison 1000 6-speed automatic. I played around with the selector lever and thumb switch to manually grab and hold lower gears, especially while descending grades to maximize engine braking. But when cruise control was engaged, the Allison automatically downshifted as needed to keep road speed close to where the cruise was set. So for the most part you can leave it alone and it'll do fine.

Two more trucks

Later that afternoon I checked out another bright-red pickup, a Vortec-powered Chevy 2500HD Extended Cab whose bed contained an 1,800-pound wood box. The truck felt a little squirrelly in high-speed curves out on I-68, but was otherwise smooth and stable. I drove west to Cumberland, an old but still thriving commercial and railroad city, and roamed around its picturesque downtown. I briefly popped into the refurbished depot that's now a tourist center as well as an Amtrak station. The Chevy was easy to park once I got used to its high 4x4 stance, and it was very easy to drive in traffic.

Next morning I had the honor of chauffeuring three other folks back to Baltimore in a shiny black GMC Denali Crewcab. Its in-dash info center told me the Vortec 6000 was delivering about 15 mpg as we motored eastward at 70 mph on I-70 - not bad for a big gasoline engine in a big pickup that was more limousine than truck. Denali is GMC's top-of-the-line trim package, and it's new to the HD series. It includes soft leather seat covers and other tastefully understated details.

There's much more to say about these trucks' 2011 mechanical upgrades. We covered those in detail in April HDT, so suffice it to say that they include the enhanced-for-2010 Duramax diesel, plus a stouter frame and stronger axles and suspensions that boost payload and towing capacities. (Read more in our March online coverage of the announcements.)

This is a very capable and comfortable series of trucks that customers should be happy to put to work, particularly if they drive as well as buy.

From the October 2010 issue of Heavy Duty Trucking magazine.