Let's establish something here and now before we proceed further. This test-drive and evaluation was conducted on this vehicle in terms of its capabilities as a tow rig, not a Rubicon-ready rock crawler. Frankly, there's only one option in the 3/4 to 1-ton class for a serious off-road truck. I think we all know what model that is. Hint: Its name ends with "Wagon." But if you're looking for a truck that will tow your toy hauler, travel trailer, dune buggy, purpose-built rock crawler or other non-street-legal vehicle across the miles, this review is for you.
At first glance, there's not a great deal distinguishing the 2011 GM Heavy Duty trucks from their 2010 counterparts. The lower-front grille openings on the diesel models are slightly larger. And the hoods feature a new design. But aside from some subtle styling tweaks, the trucks look essentially identical to last years' models. But under the skin, these trucks are about as all-new as trucks can be. Whereas last years’ models had C-section frame rails, the new models' frames are fully-boxed, stem to stern. For you live axle purists, you'll be disappointed to learn that GM's long-standing commitment to torsion bar front suspension remains for 2011. Although the basic design is carryover, the new front suspension system offers up to a 25-percent greater front axle weight rating of up to 6,000 pounds front gross axle weight, allowing a snow plow to be used on all 4WD cab configurations with the available snow plow prep package.
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The 2011 HD models' front suspension now features new forged steel upper control arms that are stronger and lighter than their predecessors. The new lower control arms are made of precision-machined cast iron to handle the greater loads. Unlike the 2010 models where only one torsion bar rate was used across all HD models, the 2011 models feature five different torsion bar rates for the various models' configurations. This helps stabilize the range of trim heights of various models under load, while enhancing appearance, handling, durability, tire wear and alignment. The trim height is adjusted on each bar via a single bolt, allowing the height to be changed to account for the weight of a snow plow or other accessories. The HD front suspension now uses a pair of urethane jounce bumpers on each side, instead of one, for improved load management; and there’s a new upper shock mount attachment design that's positively connected to the frame with two fasteners. This design eliminates squeaks and clunks, while supporting higher load capability and increased durability.
In the rear, a new larger asymmetrical leaf-spring design contributes to improved ride and handling characteristics. The asymmetrical design is derived from unequal front and rear spring half lengths, which minimize axle hop and enhance traction control efficiency.
The 2500HD models feature a two-stage leaf-spring design, while 3500HD models have a three-stage design. All models feature 3-inch-wide leaf springs that are 20-percent wider than previous models. The larger leaf-spring design supports increased rear gross axle weight ratings across the board. On the 2500HD models, the rating is 6,200 pounds – up from 6,084. On 3500HD models, the rating increases to 7,050 pounds on single-rear-wheel models and 9,375 pounds on dual-rear-wheel models – the latter representing a nearly 14-percent increase over the previous 8,200-pound rating.
Indeed, in driving the various models, both laden and unladen, the ride was remarkably comfortable and compliant for a heavy-duty truck. Even the bare-bones, vinyl seats, crank windows dump truck version we drove was remarkably smooth-riding, with very little road noise.