Used 2008 GMC Sierra 3500HD Extended Cab Review

With excellent build quality and a refined cabin to go along with its impressive work capabilities, the 2008 GMC Sierra 3500HD is a front-runner in the full-size heavy-duty pickup segment.

what's new

Other than replacing its 16-inch wheels with 17s and satellite radio becoming standard across the line, the 2008 GMC Sierra 3500HD sees no significant changes.

vehicle overview

Like David Banner in The Incredible Hulk, General Motors simply wasn't going to take it anymore. After suffering from years of criticism over the less-than-spectacular quality of its full-size truck's interiors, its pickup line underwent a startling metamorphosis last year. In the case of the GMC Sierra 3500HD, however, the morph wasn't so much green and angry as it was friendly and usable.

The Sierra's new interior was a major upgrade, and it featured higher-quality materials, tighter build quality and a sharper overall design. In addition to the attractive interior, that metamorphosis also brought new styling, a more powerful engine lineup and a stronger frame. The latter pair of improvements allowed even higher payload and towing capacities, which increased to levels that even that muscle-bound green guy would be proud of -- 5,307 pounds and 16,500 pounds (with a fifth-wheel hitch), respectively.

Compared against its archrival in the heavy-duty arena, Ford's Super Duty, the 2008 GMC Sierra 3500HD (and its Chevy Silverado twin) edges out the Ford in work capacity and has an arguably nicer interior. Either way, you can't go wrong if you're looking for a comfortable heavy-duty hauler. But if neither the GMC nor the blue oval does it for you, there's also the Dodge Ram 3500. The Ram offers nearly equal towing ability and ride comfort but lags behind in payload capacity and available cargo bed configurations.

performance & mpg

A 6.0-liter V8 (353 horsepower and 373 pound-feet of torque), matched to a six-speed automatic transmission is standard on all Sierra 3500HD trucks. Optional is the burly Duramax 6.6-liter turbodiesel V8, which boasts 365 hp and 660 lb-ft of torque. The Duramax comes paired to an Allison six-speed automatic. Properly equipped, the Duramax allows impressive payload and towing capacities of 5,307 and 16,500 pounds (with a fifth-wheel hitch), respectively.

Buyers have a choice of either rear- or four-wheel drive. The Work Truck with 4WD has a traditional floor-mounted selector for the transfer case. All other 4WD trims have Autotrac, which features an automatic setting that shifts into 4WD when wheel slippage is detected.


Antilock disc brakes are standard, though stability control, front side and side curtain airbags are not available. A Safety package that includes power-adjustable pedals and rear park assist is optional.


Based on our experience with previous Sierras, we'd expect the 2008 GMC Sierra 3500HD to provide sprightly performance, especially with the now even stronger turbodiesel V8. On long trips, the 3500HD's supple suspension should swallow bumps (even with the heavy-duty towing option) while still allowing confident, no-slop handling with a minimum of body sway through the turns. The cabins of those previously tested Sierras were impressively quiet, a characteristic sure to continue with the latest heavy-duty lineup.


Overall, the cabin's fit and finish is impressive. Simple, intuitive controls, comfortable seats, an abundance of storage cubbies, three power points and well-placed cupholders add to the user-friendly environment. There is also a one-touch, three-blink lane-change feature and standard satellite radio that make long trips more enjoyable. Rivaling the interior of a Cadillac, the plush Sierra SLT features a unique dash and door panel design with handsome wood grain and metallic accents that give this workhorse the feel of a premium luxury sedan.

edmunds expert review process

This review was written by a member of Edmunds' editorial team of expert car reviewers. Our team drives every car you can buy. We put the vehicles through rigorous testing, evaluating how they drive and comparing them in detail to their competitors.

We're also regular people like you, so we pay attention to all the different ways people use their cars every day. We want to know if there's enough room for our families and our weekend gear and whether or not our favorite drink fits in the cupholder. Our editors want to help you make the best decision on a car that fits your life.