2021 GMC Sierra 3500HD

The Sierra 3500HD is available in five trim levels: Sierra, SLE, SLT, AT4, and Denali. Prices range from $38,995 including destination for the base model to $67,995 for the range-topping Denali.

GMC offers the heavy-duty Sierra with three different cabs, two bed lengths, and a choice of single- or dual-rear wheels. All five available trims can be had on the crew cab, but the smaller two cabs are limited to the two lowest-priced trims.

Just two engines are available for the 3500HD, but both are powerful, capable choices. Those who tow regularly will want the diesel, which has a whopping 910 pound-feet of torque at the ready. Be warned, though: it costs about $10,000 over a comparable gas-powered truck.

About that gas engine: it's a 6.6-liter V8 that was first introduced last year with the new design. It's strong but can't match the diesel for pulling power, but it will haul more weight in the bed. Its 7,442 payload capacity is nothing to sneeze at.

Rear-wheel drive is standard on all but the AT4 and Denali, which are exclusively four-wheel drive.

The gas engine sticks with a six-speed automatic transmission – a gearbox still common among heavy-duty pickups. The diesel pairs up with a 10-speed automatic transmission. Those extra cogs on the diesel likely give it longer legs when it comes to burning fuel, but without official figures it's hard to comment on the gas mileage. Due to their size and weight, the EPA does not test HD trucks for their efficiency.

Three cab designs are offered in the GMC 3500HD: the two-door regular cab, the cozy double cab, and the capacious crew cab. The regular cab seats three across, but the double and crew cab models can seat five or six depending on the front seat arrangement. The crew cab is the most spacious, trading the double cab's emergency-use back seat for a full-size cabin akin to that of a Chevrolet Tahoe.

Cargo capacity is excellent, of course. The standard bed is 8 feet, 2 inches long; the smaller bed is a 6-foot, 10-inch box. Both beds feature 12 tie-downs for securing cargo. The party trick here is GMC's unique multi-way tailgate, which allows for more creative ways to store certain types of cargo that might not fit neatly into the bed with the tailgate shut.

Burly trucks like the 3500HD aren't measured against the same strict safety standards as light-duty vehicles, so they aren't tested by the NHTSA or IIHS. That means the required safety equipment is also much less stringent; the only standard piece of safety kit is a government-mandated rearview camera. Everything else is optional and bundled into a few different option packages.

The cheapest package is known as the $890 Driver Alert I, which includes front and rear parking sensors, blind-spot monitoring, and rear cross-traffic alert. It's standard on the Denali and optional elsewhere.

The Driver Alert II costs $645 and adds lane departure warning, automatic high beams, automatic emergency braking, forward collision warning, and a vibrating safety alert in the driver seat. It's available on the AT4 and SLT and comes standard on Denali.

In a nod to the times, even the cheapest workhorse 3500HD gets a 7-inch touchscreen with Bluetooth, Apple CarPlay and Android Auto, and a single USB port. Moving past the base trim brings along three more USB ports, three 12-volt outlets, and a wi-fi hot spot.

At the upper end of the trim pyramid, buyers will find an 8-inch touchscreen with Bose audio and available navigation. This setup is standard on Denali and optional on the SLT.

The $2,125 Technology Package is the flagship package that turns this truck into something sophisticated. Standard features include a surround-view camera, a bed-view camera, a head-up display, a rearview mirror camera display, and an 8-inch driver information display. Most of this equipment is standard on Denali and optional on the AT4 and SLT.

The cheapest 3500HD is a regular cab with the 8-foot bed. In base Sierra form, things aren't too luxurious: standard features are limited to a manual-adjusting bench seat, a 3.5-inch driver information center, and single-zone manual climate control. The floor is rubber, vinyl covers the seats, and even power windows and locks are optional. On the outside, LED lights, 18-inch steel wheels, black trim, chrome bumpers, and a locking tailgate are all included as well.

The only major option package is the Convenience Package ($1,950), which bundles power features, LED bed lighting, a hydraulically-assisted tailgate, cruise control, and remote keyless entry. Buyers may also be interested in the Gooseneck package that provides the attachments to tow fifth-wheel trailers.

Those who upgrade to the SLE are visually rewarded with 18-inch alloy wheels, power-adjustable trailering mirrors, body-color door handles, and deep tinted glass. Standard amenities include the multi-way tailgate, a 4.2-inch driver information center, wi-fi capability, cloud services capability, and cloth upholstery. All the features of the base model's Convenience Package come standard as well.

As to options, the SLE opens up availability of significantly more packages than the base model. These include more safety packages and and a high-tech ProGrade Trailering package that includes hitch guidance displayed the rearview camera and an in-truck trailering app.

The SLE Convenience Package includes remote start, a heated steering wheel, a power driver's seat, heated front seats, keyless entry, and dual-zone climate control. Crew and double cabs also second-row USB ports, LED roof marker lights, and LED cargo bed lighting.

The other feature-laden option is the SLE Preferred Package, which enhances in-truck tech with features like an 8-inch touchscreen with satellite and HD radio, the ProGrade Trailering features, and a power-sliding rear window.

The big jump in price for the SLT is largely due to its many additional standard features over the lower-trim models, though being only available with the crew cab does affect the spread as well. Against a comparable SLE crew cab, the upcharge is $8,000.

Still, the SLT is where things get properly luxurious. For starters, the contents of the SLE's Convenience Package and Preferred Package are all standard. From there, the SLT adds leather upholstery, memory seats, a high-definition rearview camera, an auto-dimming rearview mirror, and an alarm.

Three primary packages are on offer. The Convenience Package includes bucket seats, a console, heated and ventilated front seats, and heated rear seats. The Preferred Package bundles navigation, wireless charging, a bed camera, and a surround-view camera. The Premium Package bundles the contents of both of those and also throws in blind-spot monitoring, rear cross-traffic alert, and lane change alert.

The AT4 is more focused on off-roading than anything else. Four-wheel drive is standard, as is an off-road suspension, skid plates, a locking rear differential, hill descent control, and all-terrain tires. Interior amenities match the SLT, though the AT4 goes one step further with standard bucket seats, a front console, and heated rear seats.

The AT4 offers a Preferred Package with the same equipment found in the SLT. A Premium Plus Package includes the Premium Package, Technology Package, and Driver Alert Packages I and II.

The big-daddy Denali remains the flagship heavy-duty Sierra. It gets most features as standard, including all the features of the SLT's Preferred Package. Lots of chrome, 20-inch wheels, premium leather upholstery, and an 8-inch driver information display round out the upgrades.

The Technology Package is the only major option available.

Compare Sierra 3500HD Trims Side-By-Side