2020 GMC Sierra 2500HD

2020 GMC Sierra 2500HD Review: Towing Just Got Even Smarter

by Gabe Beita Kiser

Completely redesigned for 2020, the new GMC Sierra 2500HD offers exceptional towing and hauling capabilities to go along with enhanced technologies and a new look. Able to tow up to 18,510 pounds, the 2500HD is ready to work, so it's just as well that two engines are more than up to the task - choose between either an all-new 401-horsepower 6.6-liter V8 or the legendary 6.6-liter Duramax V8 turbodiesel with an epic 910 lb-ft of torque. GMC has also worked hard to make trailering less of a stressful affair, with an available camera system offering up to 15 views. Although spacious, the cabin doesn't feel quite as luxurious as rivals from Ford and Ram. The ride quality is also not particularly refined, especially when the big truck isn't loaded up. But for sheer heavy-hauling, it's hard to argue with the GMC's stout engines and the impressive technologies that make towing a more relaxed affair.

Read in this review:

2020 GMC Sierra 2500HD Changes: What’s the difference vs 2019 Sierra 2500HD?

As a brand new model, GMC has made a number of changes to the 2500HD to keep the truck competitive. The big news is the enhanced ProGrade Trailering system with an available 15 camera views and transparent trailer view which is said to be a segment-first. A rear camera mirror, a six-function tailgate called MultiPro, and an available 15-inch diagonal head-up display are more of the smart technologies that have been added to the range. An all-new 6.6-liter V8 gas engine produces 401 hp and 464 lb-ft, although many owners will still go for the all-conquering turbodiesel which is paired with a ten-speed automatic transmission. Also new for this generation of the Sierra 2500HD is an off-road-focused trim called the AT4. A more confident exterior is both taller and longer than before, contributing to enhanced space for occupants. The bed lift-in height has also been lowered by an inch to facilitate easier loading.

Pros and Cons

  • Smarter, more modern design than before
  • Powerful engine options and improved hauling capability
  • Slick new ten-speed automatic transmission
  • Epic turbodiesel makes light work of the heaviest loads
  • Impressive array of trailering technologies
  • AT4 off-road variant is a welcome addition
  • Cabin should have taken a bigger leap forward
  • Outward visibility isn't great
  • Ride is rather unsettled without a heavy load on board
  • Infotainment system's small screen lags behind Ram's offering

Sierra 2500HD Exterior

GMC has done a good job of modernizing the Sierra's looks without dispensing with the aggression and presence that a serious truck demands. The new grille is bigger than ever, and distinctive daytime running lights look the part. The truck does look very different depending on the trim you opt for, with the AT4's blacked-out trim contrasting with the Denali's chrome extravaganza. Wheel sizes range from 17-inch steel items to 20-inch alloys. Other available features include cargo bed LED lighting, LED headlamps and fog lamps, a power sunroof, and power-adjustable trailering mirrors with the ability to be extended.

2020 GMC Sierra 2500HD Front Angle View GMC
2020 GMC Sierra 2500HD Side View GMC
2020 GMC Sierra 2500HD Front Angle View 1 GMC
See All 2020 GMC Sierra 2500HD Exterior Photos


There's nothing shy about the Sierra 2500HD's dimensions. This is a truck that will necessitate caution in the city. Length varies between 235.5 inches for the Regular Cab to 266 inches for the Crew Cab with the long bed. The Regular Cab is 81.75 inches wide and the Double/Crew Cabs are a marginally wider 81.85 inches. Height ranges from 79.65 inches for the Crew Cab with the long bed to 79.95 inches for the Double Cab with the standard bed. There are five wheelbase lengths, starting with the Regular Cab's 141.55 inches and stretching to 172 inches for the Crew Cab with the long bed. The regular cargo box is 82.2 inches long at the floor, increasing to 98.27 inches for the long box. The cargo box width at the floor is 71.4 inches and the width at the wheel housings is 51.85/50.55 inches for the standard/long beds. Ground clearance, front and rear, is just over 10 inches for all variants. The lightest model is the gas-powered, rear-wheel-drive Regular Cab at 6,105 pounds and the heaviest is the four-wheel-drive, diesel-powered Crew Cab with the long bed at 7,886 lbs.

Exterior Colors

The Sierra's color palette is fairly basic, extending to ten shades, although some are only available on certain trims. Summit White is the standard color, and for an extra cost, there's Onyx Black, Cardinal Red, Pacific Blue Metallic, Quicksilver Metallic, Carbon Black Metallic, Dark Sky Metallic, Red Quartz Tintcoat, Brownstone Metallic, and White Frost Tintcoat. Onyx Black is the cheapest at $195, while White Frost Tintcoat will add $1,095 to the base price.

Sierra 2500HD Performance

The Sierra 2500HD is offered in both two-wheel-drive and four-wheel-drive configurations, along with a choice of two engines: a new gas-fed 6.6-liter V8 with 401 horsepower and 464 lb-ft of torque, and an optional 6.6-liter V8 turbodiesel with outputs of 445 hp and 910 lb-ft. Both engines are strong, but the turbodiesel is the much more appealing option if heavy towing will be a regularity. According to independent testing, unladen, this version will hit 60 mph in comfortably under eight seconds and, according to GMC, you'll be able to get to 60 mph in a commendable 19.9 seconds while pulling a trailer of 18,000 pounds. Conventional towing capacity is 14,500 lbs for most models, rising to 18,500 lbs for the Crew Cabs fitted with the diesel engine. Fifth wheel/gooseneck trailering works out to a maximum 18,510 for the diesel Regular Cab with rear-wheel-drive.

2020 GMC Sierra 2500HD Front Angle View 2 GMC
2020 GMC Sierra 2500HD Rear Angle View GMC
2020 GMC Sierra 2500HD Wheel GMC

Engine and Transmission

A big truck needs big power and the Sierra 2500HD doesn't disappoint. The standard, all-new V8 gasoline engine displaces 6.6-liters and produces 401 hp and 464 lb-ft of torque. It's paired with a six-speed automatic transmission. As solid as these outputs are, they're dwarfed by the 6.6-liter V8 turbodiesel's 445 hp and staggering 910 lb-ft. The diesel also gets a new Allison ten-speed automatic transmission.

The diesel is noticeably stronger when hauling a load and the increased gear ratios help to keep the engine within its peak powerband. Without a heavy load, acceleration in both models is brisk enough and the big truck gets up to speed with minimal fuss. In towing/haul mode, the diesel can put down its maximum torque off the line, which is why it rarely feels taxed even when towing massive loads. The same can't be said of the gasoline V8, which has to make do with four fewer gears and virtually half the torque output. More moderate towing is better suited to this variant. Without a doubt, the diesel and ten-speed automatic pairing is the powertrain of choice.

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

Handling and Driving Impressions

Dynamic expectations of a massive truck with considerable hauling capabilities are not high, but even so, the Sierra is a bit disappointing. On the open road where there's plenty of space and the surface is smooth, the GMC is pleasant enough to pilot. On bumpier roads, the truck fails to settle down, especially when unladen - there's a bounciness to proceedings that never lets you forget that you aren't in a luxury sedan. When loaded up with cargo or pulling a heavy trailer, matters improve somewhat, but it never approaches the compliance of the Ram 2500. Through the corners, the Sierra hangs on reasonably well considering its heft and the steering is light enough to maneuver the truck around town, but the rack is also rather numb at higher speeds so it requires some attention from the driver to stick to your chosen path. The truck is quiet enough under a variety of conditions, but again, not remarkable in this area. That's really the gist of the Sierra 2500HD - it doesn't do anything badly, but neither does it stand out in any one area dynamically. Braking in regular driving is fine, but when towing a heavy load, the spongy pedal feel is disconcerting and the system only really bites towards the end of the pedal's travel - considering how quickly the turbodiesel can pick up speed, we would have liked this to be complemented by more confidence-inspiring brakes.

Sierra 2500HD Gas Mileage

EPA-rated economy numbers for the Sierra 2500HD don't exist, but you shouldn't expect it to be anything less than heavy on fuel. Real-world reports of economy numbers weren't available for the 2020 Sierra 2500HD at the time of writing, but the carryover turbodiesel averaged around 14.9 mpg in the 2019 model, so you can expect similar with the new truck. Gas tank size varies depending on the configuration you go for, but a 36-gallon tank is available and, at the same consumption seen with the 2019 model, this would equate to a range of about 536 miles. The gasoline engine will use even more fuel, but both models' consumption will be dramatically affected by the driving style and the weight of the load being hauled.

  • Fuel Tank Capacity
    36.0 Gallons
* 2020 GMC Sierra 2500HD 2WD Crew Cab 159"

Sierra 2500HD Interior

The new Sierra may turn more heads on the highway than before, but the blocky and function-over-form interior hasn't taken the same leap forward. Space utilization isn't the problem, as there's plenty of legroom and headroom, especially in the Crew Cab. Rather, the similar (and ordinary) design and middling materials are what disappoints. It's all easy enough to use but simply doesn't feel as special as Ram's HD trucks. As impressive as the multi-view trailering camera system is, it's also displayed on a rather small central screen. The Denali trim feels more premium, but it's merely a few classy touches on top of a rather basic foundation. The base Regular Cab is spartan, with a two-speaker sound system, manual windows, and vinyl seats. More expensive trims have many features, from wireless charging to a premium sound system, power seats, and even an available rear-seat entertainment system.

2020 GMC Sierra 2500HD Dashboard GMC
2020 GMC Sierra 2500HD Dashboard 1 GMC
2020 GMC Sierra 2500HD Infotainment System GMC
See All 2020 GMC Sierra 2500HD Interior Photos

Seating and Interior Space

The Regular Cab seats three and the Double/Crew Cabs seat five or six occupants. The Regular Cab has a 40/20/40 split-bench front seat, while other models have either a front bench seat with a covered armrest or two front bucket seats with a center console. The seats themselves have good padding and sufficient lumbar support to take the strain out of longer journeys - they also help compensate for the Sierra's often bouncy ride. There's plenty of legroom and headroom for all occupants, and the rear floor is flat for improved foot space. Being a big truck, ingress and egress does require some care. The driving position is high-set, but outward visibility isn't the best: there's a giant hood that is difficult to see over, broad roof pillars, and an undersized rearview mirror.

  • Seating capacity

Interior Colors and Materials

The base Sierra has vinyl-covered seats, the SLE has cloth upholstery, and trims above this level have perforated leather. Similarly, the base model misses out on a leather-wrapped steering wheel, firmly positioning this variant as a durable workhorse. Although there are some soft-touch plastics and dashboard stitching in place, the materials aren't as premium as in Ram's new-generation trucks. That said, build quality is appropriately sturdy.

At a base level, Jet Black is the only color available for the interior. The SLE trim adds Dark Walnut/Slate for a less obviously truck-like appearance, and the off-road-focused AT4 has a Jet Black interior with Kalahari accents. The range-topping Denali can be optioned with Dark Walnut/Dark Ash Gray seats. Even though the Denali gets wood trim, it's rather plasticky in look and feel and doesn't match the top-line Ford and Ram trucks.

Sierra 2500HD Trunk and Cargo Space

The bigger Sierra 2500HD has plenty of space for cargo. The standard six-foot-eight bed has 69.5 cubic feet of space, and this grows to 83.5 cubes for the eight-foot-two long bed thanks to an additional 16 inches of length.

There's a decent amount of small-item storage in the cabin, although again, this varies depending on the trim and body style you go for. Some models have under-seat storage front and rear, and others have a large reconfigurable center console in place of the front bench seat. In the more basic trims, the Crew Cab has a 60/40-split-folding rear seat.

2020 GMC Sierra 2500HD Backup Camera Screen GMC
2020 GMC Sierra 2500HD Backup Camera Screen 1 GMC
2020 GMC Sierra 2500HD Backup Camera Screen 2 GMC

Sierra 2500HD Infotainment and Features


From the basic Sierra to the fully-loaded Denali, the Sierra 2500HD's feature count varies from spartan workhorse to a comfortable truck for the family. The entry-level Sierra Regular Cab has a four-way manual driver's seat, manual windows, a rearview camera, and single-zone climate control. SLE trim adds cruise control, power windows, and remote keyless entry. The SLT adds quite a few goodies, from ten-way power front seats to dual-zone automatic climate control. Other available features on the higher trim levels include heated seats front and rear, a heated steering wheel, a power sunroof, a power-sliding rear window, wireless charging and ventilation for the front seats.


The base Sierra uses a seven-inch touchscreen infotainment system while all other trims get an eight-inch touchscreen. The screen size looks rather outdone next to rivals like Ram, but the system is at least easy to fathom. All models get Bluetooth audio streaming, an AM/FM stereo, a dash-mounted USB port, Apple CarPlay, and Android Auto. Higher trims get USB ports in the second row as well. SLT trim adds SiriusXM, HD radio, and voice-activation of selected functions. Navigation is only standard on the Denali but is available for the SLT and AT4. While the base Regular Cab only has a two-speaker audio system, higher trims have a six-speaker system and the Denali gets a seven-speaker Bose sound system. Wireless charging and a WiFi hotspot with 4G LTE data are available.

Sierra 2500HD Problems and Reliability

It's too early to evaluate the new Sierra 2500HD's reliability, but the 2019 model did hold a strong J.D. Power rating of 84/100. The 2020 model has, however, been subject to one recall already - if the seat belt pre-tensioners deploy, there is a chance that escaping hot gas could ignite interior materials.

GMC's limited warranty is for three years or 36,000 miles, whichever comes first. A five-year/60,000-mile powertrain/drivetrain warranty is also included, although this is extended to 100,000 miles for the turbodiesel and/or qualified fleet purchases. Corrosion protection is for three years/36,000 miles, with six-year/100,000-mile rust-through coverage. Finally, you get one scheduled maintenance visit in the first year.

Sierra 2500HD Safety

The Sierra 2500HD has yet to be evaluated for crash safety by local authorities. Promisingly, the IIHS awarded the 2019 GMC Sierra 1500 a Good rating in five of six crashworthiness tests, so we see no reason why the 2500HD wouldn't match or improve on these results.

Key Safety Features

Standard safety features include six airbags, a rearview camera with hitch guidance, LED daytime running lamps, electronic stability control with traction control, tire pressure monitoring, and a teen driver feature to encourage better driving behavior or limit certain features. An HD rearview camera is fitted to higher trims and includes dynamic guidelines. The range-topping Denali also has automatic emergency braking, forward collision alert, a following distance indicator, front and rear park assist, lane departure warning, lane change alert with blind-spot monitoring and rear cross-traffic alert. The available ProGrade trailering system features 15 different camera views along with an innovative transparent trailer view to significantly improve situational awareness when towing. We would have liked to have seen adaptive cruise control on the list of safety features, though.

Verdict: Is the 2020 GMC Sierra 2500HD a good Truck?

A definite improvement over the previous model, the updated Sierra 2500HD is a hard-working truck with really impressive towing capabilities. The new looks are a success - the Sierra is as imposing as the closely related Chevrolet Silverado 2500HD, but also neater and more cohesive. The 6.6-liter turbodiesel engine (with its mammoth 910 lb-ft of torque) and the excellent available camera system make this truck a tower's dream. Three body styles, two bed sizes, and a range of trims mean there is a Sierra 2500HD to fit most needs and budgets. It's only once you climb aboard that the Sierra starts to disappoint. The interior is spacious and solid, but it isn't as luxurious as rivals from Ram and Ford and we wish that GMC had fitted a bigger infotainment screen to complement the fancy camera system. On the road, the Sierra also offers an only average driving experience. Anything less than a smooth and straight road, and the Sierra feels either too cumbersome or rides too bouncily. These aspects prevent GMC's offering from topping the class, but the Sierra 2500HD remains a great truck and is well worth a test drive.

What's the Price of the 2020 GMC Sierra 2500HD?

The cheapest model in the range is the base Sierra Regular Cab 2WD which carries an MSRP of $35,600. Next is the slightly less basic SLE at $40,000. The mid-range SLT costs $50,600 and, like all other trims from this level up, can't be paired with the Regular Cab body style. The off-road-focused AT4 costs $57,700, followed by the range-topping Denali at $63,700. All prices exclude tax, licensing, registration, optional extras, and a destination charge of $1,595.

On the base Sierra Regular Cab, upgrading to 4WD costs $2,800 and the turbodiesel engine will add another $12,115 to the price. Also on this model, the Double Cab will add $2,600 to the base price and the Crew Cab adds $4,400. Between the different trims, you can expect similar increases if optioning 4WD, a different body style, or the turbodiesel engine. The most expensive model is the Crew Cab Denali with 4WD, the turbodiesel engine, and the longer bed which will set you back $73,650 excluding the destination charge.

2020 GMC Sierra 2500HD Models

The Sierra 2500HD comprises five trims: the base Sierra, SLE, SLT, AT4, and Denali. All are fitted with a 6.6-liter gasoline V8 developing 401 hp and 464 lb-ft of torque, paired with a six-speed automatic. A mighty 6.6-liter V8 turbodiesel with 445 hp and 910 lb-ft (along with a new ten-speed automatic) is optional.

The entry-level Sierra is the workhorse of the range and is available in all three body styles: Regular Cab, Double Cab, and Crew Cab. This trim gets 17-inch silver-painted steel wheels, black exterior trim, chrome front and rear bumpers, and LED headlamps/daytime running lamps. Inside, there's a two-speaker sound system (Regular Cab) and basic vinyl-upholstered seats, along with a seven-inch touchscreen, rearview camera, single-zone climate control, and manual window winders (Regular Cab only). The SLE adds 17-inch alloy wheels, power-adjustable vertical trailering mirrors, body-color door handles, and a tailgate with EZ lift and lower assist. Inside, the less spartan SLE gains cloth-covered seats, a front covered armrest, an eight-inch touchscreen, cruise control, and a leather-wrapped steering wheel.

The mid-range SLT is a welcome step up in features, although this variant is only available in Double Cab and Crew Cab configurations. It gets 18-inch machined alloy wheels with gloss black accents, cargo bed LED lighting, chrome mirror caps/door handles, LED fog lamps, and a power-folding/-extending feature for the trailering mirrors. The more comfortable interior is fitted with ten-way power front seats, the premium infotainment system with HD radio, dual-zone automatic climate control, and heating for the front seats and steering wheel. The new AT4 trim has been set up for enhanced off-road capability and is only available in 4WD and Crew Cab configurations. This variant gets an Autotrac two-speed transfer case, hill descent control, an off-road suspension, a spray-on bedliner, front bucket seats with ventilation (reducing seating capacity to five), and heated rear outboard seats.

Topping the range is the Denali, also only available as a 4WD Crew Cab. It gets Intellibeam headlights, polished exhaust tip, automatic emergency braking and LED roof marker lamps. The Denali also enjoys the best-specified cabin in the range with standard navigation, a power sliding rear window, wireless charging, and a raft of driver aids like lane departure warning and rear cross-traffic alert.

Trim Engine Transmission Drivetrain Price (MSRP)
6.6-liter V8 Gas
6-Speed Automatic
Rear-Wheel Drive
Four-Wheel Drive
6.6-liter V8 Gas
6-Speed Automatic
Rear-Wheel Drive
Four-Wheel Drive
6.6-liter V8 Gas
6-Speed Automatic
Rear-Wheel Drive
Four-Wheel Drive
6.6-liter V8 Gas
6-Speed Automatic
Four-Wheel Drive
6.6-liter V8 Gas
6-Speed Automatic
Four-Wheel Drive
See All 2020 GMC Sierra 2500HD Trims and Specs

Additional Packages

There's more choice and customization to be had with GMC's range of optional packages and standalone features. On the base Sierra Regular Cab, the Driver Alert Package I goes for $890 and packs in driver aids like front/rear park assist and rear cross-traffic alert. For $1,950, the Convenience Package adds power windows/locks, LED cargo box lighting and remote keyless entry, among other items. For enhanced towing capacity, the Gooseneck/Fifth Wheel Package costs $1,365.

The SLE Regular Cab offers similar gooseneck/driver alert packages but with minor cost differences. This trim additionally gets access to the SLE Convenience Package at $2,405 (power seats, keyless open/start, dual-zone climate control, heated steering wheel and more), the $785 Preferred Package (premium infotainment, 120-volt power outlet, HD rearview camera, power rear sliding window and more), the ProGrade trailering system at $710, and the Remote Start Package at $525. There are over ten packages for the mid-range SLT. The most tempting of those are the SLT Premium Plus Package which costs $6,670 (this package bundles several smaller packages together), the Texas Edition SLT Premium Plus Package at $6,670 (similar to the previous package but with bespoke badging), the Technology Package at $2,125 (head-up display, rear camera mirror, bed-view camera, and more), and the SLT Convenience Package at $1,370 (front bucket seats with ventilation and more). These prices are all for the SLT Double cab, with the Crew Cab asking similar prices per package.

Like the other trims, the AT4 gets its own bespoke packages. At $4,215, the AT4 Premium Package features the likes of navigation, 20-inch wheels, and navigation. The Technology Package goes for $2,125, just as on the SLT. The AT4 Preferred Package costs $1,475 and packs in features like wireless charging and a Bose premium sound system. Other upgrades like snowplow prepping and a gooseneck hitch further enhance this model's capabilities. On the range-topping Denali, the Denali Ultimate Package goes for $2,870 and contains amenities like a sunroof, rear camera mirror, and HD surround vision. The Technology Package costs $1,875 on this variant and brings with it a 15-inch multi-color head-up display.

An array of individual accessories are available to suit just about every kind of towing requirement, from various sizes of hitch ball mounts to wiring harnesses. Over 50 individual bed products can enhance your use of this space.

What GMC Sierra 2500HD Model Should I Buy?

The mid-range SLT is an attractive option since it already contains many of the most essential features as standard while leaving some room for customization without the upper trims' mega price tags. We'd spec our Crew Cab SLT with the awesome turbodiesel engine, the Driver Alert Package I for access to useful driver aids like blind-spot alert, and the Technology Package with its expansive head-up display. The total cost works out to $62,290 excluding the destination charge. Of course, if you must have the 4WD drivetrain, that number will increase.

2020 GMC Sierra 2500HD Comparisons

GMC Sierra 1500 GMC
Chevrolet Silverado 2500HD Chevrolet

2020 GMC Sierra 2500HD vs GMC Sierra 1500

If you don't need all of the 2500HD's towing capacity, it's the smarter choice to go for a higher-spec 1500. Starting at under $30,000, the 1500 can still tow up to 12,100 pounds (6,400 lbs less than the best of the 2500HD range). The 1500 also offers a wider range of engines, starting with a 310-horsepower 2.7-liter turbo. Being the lighter truck, it's also more economical than the 2500HD. Both have spacious cabins but rather dull dashboards, but it's nice to know that the 2500HD's highlights (the transparent trailer view and the six-function multi-pro tailgate) are also available on the smaller truck. The 2500HD is the towing king here and benefits from that special 6.6-liter turbodiesel, but other than the numbers game, these are comparable trucks so choose the 1500 if your needs aren't that extreme.

See GMC Sierra 1500 Review

2020 GMC Sierra 2500HD vs Chevrolet Silverado 2500HD

These are two very closely matched trucks. Not only do they share the same underpinnings and powertrains, but even the same infotainment system. The Silverado does start at $1,500 less, however, and that's quite a difference for two trucks that are essentially the same. The biggest differences are of course the designs, and it's up to you to decide which one speaks to you more. The Sierra also has the edge for interior quality, although neither are class-leading in this respect. GMC's multi-pro tailgate is a great feature, but is it worth the $1,500 price premium? We're not so sure. Whichever truck you choose, you'll get superb towing capacities, powerful engines, and enough space for your family and their cargo.

See Chevrolet Silverado 2500HD Review

GMC Sierra 2500HD Popular Comparisons

$35,600 - $63,900
Price Range (MSRP)
GMC Sierra 2500HD
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