2021 GMC Sierra 3500HD

2021 GMC Sierra 3500HD Review: A Big Truck For Big Men

The GMC Sierra 3500HD range of trucks sits at the very top of the GMC food chain. These heavy-duty trucks have been designed to put in the work, tow entire villages, and annoy hybrid owners. The new Sierra 3500HD retains some of the old features we've come to love, such as that monumentally powerful 6.6-liter V8 turbo-diesel engine, which is now mated to a brand-new and beautifully smooth ten-speed automatic transmission. For 2021, GMC adds some cool new trailer-assistance tech. The Sierra excels at what it has always done best, which is to work hard, carry a lot of stuff, and not break down every second week. The 2021 model is naturally pitted against its sibling, the 2021 Chevrolet Silverado 3500HD, which brings its own pros and cons to the table.

Read in this review:

2021 GMC Sierra 3500HD Changes: 🚙What’s the difference vs 2020 GMC Sierra 3500HD?

The GMC Sierra was completely redesigned for 2020 to bring it up to date in its class. As such, not much changes for 2021, except for some detail specification, trim, spec, and color changes. New trailer-assistance safety features have become available, such as a trailer-length indicator and jack-knife alert, and towing capacity is up. The multi-purpose MultiPro tailgate has now also been added as standard equipment to the SLE trim. Denali trim gets a bed-view camera and an HD 360-degree camera and this trim can now also be had in a special Diamond Edition with power-retractable running boards and black 20-inch alloys. A high-clearance step and mud tires have been added to the off-road AT4 trim's options. Lastly, three new paint colors are added for 2021.

Pros and Cons

  • Advanced trailer-assistance features
  • Powerful V8 diesel option
  • Great ten-speed automatic
  • Massive towing capability
  • The brakes could be better
  • Contentious styling
  • Disappointing interior

Best Deals on Sierra 3500HD

2021 GMC Sierra 3500HD Trims

See trim levels and configurations:

Trim Engine Transmission Drivetrain Price (MSRP)
Base
6.6L V8 Gas
6-Speed Automatic
Rear-Wheel Drive
Four-Wheel Drive
$37,400
SLE
6.6L V8 Gas
6-Speed Automatic
Rear-Wheel Drive
Four-Wheel Drive
$42,800
SLT
6.6L V8 Gas
6-Speed Automatic
Rear-Wheel Drive
Four-Wheel Drive
$54,600
AT4
6.6L V8 Gas
6-Speed Automatic
Four-Wheel Drive
$60,300
Denali
6.6L V8 Gas
6-Speed Automatic
Four-Wheel Drive
$66,700

Sierra 3500HD Exterior

The new Sierra 3500HD is bolder than ever: the front grille is large, and for 2021 it is still flanked by a set of LED headlamps with a signature C-shape, which adds a modern touch to this absolute hulk of a truck. SLE models and upwards get a world-first six-function MultiPro tailgate. SLT models and up get GMC's ProGrade trailering system with an in-vehicle trailering app and an integrated trailer brake. AT4 Models get a two-inch lift, and top-of-the-range Denali models receive a bunch of chrome bits on the door handles, side steps, and around the front grille. Denali models also get a deep-tinted rear window, a polished exhaust tip, and smoked Amber LED roof marker lamps. Paint colors have been reshuffled a little; for example, Red Quartz Tintcoat has been replaced by Cayenne Red Tintcoat and Dark Sky metallic is a new color.

2021 GMC Sierra 3500HD Front View Driving GMC
2021 GMC Sierra 3500HD Side View Driving GMC
2021 GMC Sierra 3500HD Frontal Aspect GMC
See All 2021 GMC Sierra 3500HD Exterior Photos

Dimensions

As with most trucks on the market today, buyers get an infinite amount of cab and bed configurations, so there's a ton of dimensions to list. We'll provide you with the shortest and longest ones: The 2WD Sierra 3500HD with the Regular Cab and long bed measures in at 235.5 inches while the Crew Cab with the long bed stretches out to a lanky 266.1 inches. Wheelbase measurements range from 141.55 to 172 inches, and the total width without mirrors is 81.8 inches, while ground clearance sits around 11 inches. Curb weights range between 6,231 pounds for 2WD regular cab trucks, and a massive 8,355 lbs for 4WD diesel long bed crew-cab trucks. The weight difference between gas and diesel-powered trucks averages around 800 to 1,000 lbs.

  • Length 235.5 in
  • Wheelbase 141.6 in
  • Height 80.9 in
  • Max Width 81.8 in

Exterior Colors

Sierra 3500HD Performance

2021 GMC Sierra 3500HD Side Angle Driving GMC
2021 GMC Sierra 3500HD Forward View GMC
2021 GMC Sierra 3500HD Wheel GMC

Engine and Transmission

For 2020, the Sierra 3500HD received an all-new 6.6-liter gas V8 engine, which produces a stout 401 hp and 464 lb-ft of torque available from 4,000 rpm. Power is sent to the rear or all four wheels depending on the drivetrain configuration. The new V8 gets the job done, but needs to rev out before things start going, which is not ideal for towing. If you're serious about towing, then you'll have to go for the 6.6-liter Duramax turbodiesel V8 engine, it cranks out 445 hp and a mammoth 910 lb-ft of torque available from only 1,600 rpm. Diesel-powered trucks come with a ten-speed auto transmission. With all that torque on tap, the Regular Cab Heavy-Duty Diesel 2WD will tow a maximum of 36,000 lbs off of a gooseneck hitch.

  • Engines
    6.6L Turbo V8 Diesel, 6.6L V8 Gas
  • Transmissions
    10-Speed Automatic, 6-Speed Automatic
  • Drivetrains
    4X4, RWD

Handling and Driving Impressions

The 3500HD will never be expected to be a canyon carver or track weapon, but those who buy these trucks will expect solid, stable, and predictable handling that won't get upset easily when towing heavy gear. The new Sierra 3500HD feels comfortable and unhindered when cruising around town, and out on the highway it feels planted, especially when you've got dual tires on the back. GMC's ProGrade trailering system and digital variable steering assist, which automatically adjusts steering weight and responsiveness based on road conditions and speed, help keep things in check when there's a heavy load in the back. Diesel trucks get exhaust braking, which assists in downhill speed-moderation.

Sierra 3500HD Gas Mileage

The EPA doesn't require gas mileage estimates for full-size trucks such as the Sierra, but you can expect to see figures ranging from the low to high teens depending on cab, bed, engine, and drivetrain configuration.

  • Fuel Tank Capacity
    36.0 Gallons
* 2021 GMC Sierra 3500HD 2WD Regular Cab 142"

Sierra 3500HD Interior

2021 GMC Sierra 3500HD Central Console GMC
2021 GMC Sierra 3500HD Infotainment System GMC
2021 GMC Sierra 3500HD Interior Wooden Trim GMC
See All 2021 GMC Sierra 3500HD Interior Photos

Seating and Interior Space

There's no doubt that the 3500HD is an intimidatingly large truck, but does its size mean lots of interior space? Front headroom measures around 43 inches and front legroom comes in at an impressive 44.53 inches. That's more than enough for even the largest of drivers. Headroom in the second row is just above or below 40 inches, depending on cab choice, which is still pretty impressive. The second-row legroom remains generous at 43.4 inches in the Crew Cab, although things get a lot tighter in the Double Cab which offers only 35.24 inches.

  • Seating capacity
    3-seater
  • Front Leg Room 44.5 in
  • Front Head Room 43.1 in

Sierra 3500HD Trunk and Cargo Space

Buyers can choose between standard and long-bed configurations. Standard beds are 82.2 inches long when measured along the floor, while long beds measure 98.27 inches. Bed width is 71.4 inches across the range, shrinking to between 50.55 and 51.85 inches between the wheel housings. Total cargo volume for standard bed trucks is 69.5 cubic feet, while long bed trucks offer 83.5 cubes. If you're wondering exactly how much stuff you can put on the back, the answer is anywhere between 4,013 lbs and a massive 7,442 lbs.

Inside there's a large center console storage box, glove box, door pockets, and cupholders. The 2021 Sierra 3500HD will carry all of your stuff, and then some.

2021 GMC Sierra 3500HD Top View GMC
2021 GMC Sierra 3500HD Backup Camera Screen GMC
2021 GMC Sierra 3500HD Backup Camera Screen 1 GMC

Sierra 3500HD Infotainment and Features

Features

The feature list on the 2021 Sierra 3500HD varies between basic workhorse and decked-out luxury-barge. Standard features on the base model include LED daytime running lights, a locking tailgate, a four-way manually adjustable driver's seat, and single-zone climate control. The hardcore AT4 truck gets 18-inch alloy wheels with 18-inch LT275/70R18E all-terrain, Blackwall tires. The interior of the AT4 includes 4G LTE Wi-Fi connectivity, cruise control, dual-zone climate control, ten-way power-adjustable heated and ventilated front seats, and heated outboard rear passenger seats. If you're looking for a truly premium experience, then the only way to go is Denali: this top-spec trim gets chrome door handles, IntelliBeam auto headlights, and a Bose premium audio system, as well as driver-assistance features like forward-collision assist, and lane-departure warning.

Infotainment

Just because it's a truck doesn't mean you can't have a banging infotainment system. The base model Sierra 3500HD comes fitted with a seven-inch touchscreen display that features standard Apple CarPlay, Android Auto, and Bluetooth streaming. Sound is channeled through a six-speaker system, and the driver gets a 3.5-inch driver info screen, growing to 4.2 inches in SLE models. SLE models get an upgraded eight-inch infotainment system with AM/FM and SiriusXM satellite radio. For those who seek more from their truck than pure utility, the Denali offers a truly premium experience, and that goes for its infotainment system as well; the eight-inch touchscreen display now gets integrated navigation and a seven-speaker premium Bose sound system with a Richbass woofer.

Sierra 3500HD Problems and Reliability

There have been two recalls issued so far in 2021 for Sierra 3500HD, both for seat-belt issues. Incorrect bolts might have been used to secure the seat belts and the front center seat-belt bracket may not be properly secured. J.D. Power gives the 2021 3500HD a solid overall score of 85 out of 100 and 81/100 for quality and reliability. GMC will cover it's 2021 3500HD with a three-year/36,000-mile basic warranty, which includes a five-year/60,000-mile drivetrain warranty, and a five-year/60,000-mile roadside-assistance plan.

Warranty

  • Warranty Note:
    Preliminary 2021 Warranty \ 
  • Basic:
    3 Years \ 36,000 Miles
  • Drivetrain:
    5 Years \ 60,000 Miles
  • Drivetrain Note:
    HD Duramax Diesel: 5 Years \ 100,000 Miles; Qualified Fleet Purchases: 5 Years
  • Rust-Through:
    6 Years \ 100,000 Miles
  • Corrosion:
    3 Years \ 36,000 Miles
  • Roadside Assistance:
    5 Years \ 60,000 Miles
  • Roadside Assistance Note:
    HD Duramax Diesel: 5 Years \ 100,000 Miles; Qualified Fleet Purchases: 5 Years
  • Maintenance Note:
    1 Year \ 1 Visit

Sierra 3500HD Safety

Neither the NHTSA or IIHS are required to test the 3500HD's ability to keep its occupants safe in the event of a crash, due to its classification as a heavy-duty truck. But owners can rest assured that they'll be kept safe; safety features on the 3500HD include six airbags, stability and traction control, and teen-driver monitoring. Advanced features such as rear cross-traffic assist and lane-departure warning are standard on Denali trucks.

Verdict: 🏁Is 2021 GMC Sierra 3500HD a good Truck?

The GMC 3500HD brings a lot to the table but falls short of its competitors in some areas. From the outside, the 3500HD looks mean, and is physically wide and tall. We'll reserve judgment on the looks, but it's sure to divide opinions. What's more important is what lies underneath the shell: the new-for-2020 V8 engine produces 401 hp and 464 lb-ft of torque. It performs well enough at hauling along the 3500HD in all of its body configs but disappoints when it comes to towing the heavier stuff. For that, you'll have to go with the trusted 6.6-liter turbo-diesel V8, which gets mated to a ten-speed auto, which is a pleasure to use. On the inside, the 3500HD disappoints the most; it feels cheap when compared to its stablemate the Silverado, and just can't match industry standards. In a market that's offering premium sedan-rivaling interiors, GMC seriously needs to step up its game. At the end of the day, the 3500HD does perform well at its core duty, which is carrying and towing heavy stuff. It might not be as nice inside the cabin, but the drivetrain works well, it's a pleasure to drive, and it won't let you down when the going gets tough.

🚘What's the Price of the 2021 GMC Sierra 3500HD?

The price range on the 2021 GMC Sierra 3500HD varies wildly due to its massive number of trim, engine and body style options, so you should have no trouble finding the perfect truck for your specific needs. The cheapest seat in the house belongs to the base model 2WD Regular Cab long bed, which goes for $37,400. At the other end of the spectrum lies the Denali which starts at $67,195 for the single rear wheel truck, but goes up to $77,850 for the Dually. Fully specced, the Denali can reach prices close to $90,000. These prices exclude a destination charge of $1,695.

2021 GMC Sierra 3500HD Models

See All 2021 GMC Sierra 3500HD Trims and Specs

🚗What GMC Sierra 3500HD Model Should I Buy?

The question of which truck you should buy becomes a near-on impossible task when it comes to heavy-duty machines such as the 3500HD. There are countless configurations to choose from, which means that there will be something for everybody. If you're after a basic work truck, then you should look at getting a base model Sierra with a single cab and long bed. If you use your truck for business and pleasure, a good midrange option would be the SLT Double Cab with a long bed, which offers enough space for the family, and enough cargo space to get the job done. If you're in it purely for the street cred, then you can't go with anything less than a dual-rear-wheel 4WD Denali with a crew cab and long bed. With a Bose sound system, leather seats, and power and heated everything, you're sure to make some sort of statement.

2021 GMC Sierra 3500HD Comparisons

Chevrolet Silverado 3500HD
GMC Canyon GMC
CompetitorHorsepowerMPGPrice (MSRP)
GMC Sierra 3500HD401 hpTBC$37,400
Chevrolet Silverado 3500HD 401 hpTBC$36,500
GMC Canyon 200 hp19/25 mpg$26,800

2021 GMC Sierra 3500HD vs Chevrolet Silverado 3500HD

The Sierra and Silverado 3500HD are basically the same truck with a different face, so most buyers will go on brand loyalty when it comes to making the final decision - but there are some considerations to take in mind. The Chevy is slightly shorter and has a smaller turning circle, which makes it easier to maneuver in tight spaces such as building sites. The interior of the Silverado shares its basic design with the GMC, but we'd argue that it offers superior quality, fit and finish. The GMC, in extended-cab configuration, offers more leg and headroom space, which could come in handy for larger families or long road trips with the bros. The Silverado will hurt your wallet slightly less than the GMC. It's a close call on which truck to go for here, and we think that the badge on the rear liftgate will be the most important factor.

See Chevrolet Silverado 3500HD Review

2021 GMC Sierra 3500HD vs GMC Canyon

The Sierra 3500HD and Canyon live at opposite ends of the trucking spectrum. Whereas the Sierra 3500HD was built specifically to tow heavy loads and work long hours on building sites and behind the scenes at drag racing events, the Canyon was designed to be enjoyed by adventurous families and thrill-seekers looking for a robust and capable truck that offers as much comfort as it does practicality and ease of use. Just by looking at the available engine choices on the Canyon, you can see where we're going; there's a 200-hp 2.5-liter four-pot, a 2.8-liter turbodiesel four producing 181 hp and 369 lb-ft of torque, or a 3.6-liter V6 engine with 308 hp and 275 lb-ft of torque. These aren't engines designed to pull big loads. The driving characteristics also differ: the Sierra 3500HD is piloted, whereas the Canyon gets driven - its lighter, more nimble, and easier to operate on a daily basis. Get the Canyon if you want to go on adventurous holidays in the woods, but get the Sierra 3500HD if you need to build that cabin first.

See GMC Canyon Review

GMC Sierra 3500HD Popular Comparisons

The most popular competitors of 2021 GMC Sierra 3500HD:

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