2020 GMC Sierra 2500HD

GMC has an evident approach when it comes to building heavy-duty trucks: make them big, make them bold, make them capable, and make using them as stress-free as possible for practical use. For everyday work, the newly redesigned 2500HD is bigger, features a lower bed lift-in height, a roomy interior, and an optional six-function tailgate. GMC also wants to take the hassle out of towing using tech and clever use of cameras. It's succeeded on all fronts.

Power in the base models comes from an all-new 6.6-liter V8 gasoline engine producing 401 horsepower and 464 lb-ft of torque. However, for those that need to pull really big loads, an available 6.6-liter V8 turbodiesel makes 445 hp and a monstrous 910 lb-ft of torque to rival the best on offer in the form of the Ram 2500 and Ford F-250. GMC isn't neglecting the truck owners that need to get off the road anymore and has brought the AT4 off-road trim to the Sierra 2500 HD for 2020.

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.

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 266.1 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.

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 and the other premium colors vary in between.

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.

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.

Our test vehicle came with the 6.6-liter turbodiesel engine and Allison transmission combination and in the AT4 off-road trim. The turbodiesel is the engine GMC expects most of its heavy-duty requiring customers to choose, and it is a brute. However, it is well refined and the power, the endless power, is easy to control with or without a big load behind. Part of that is down to the pairing with the Alison transmission, which is remarkably smooth when it shifts. We didn't have anything huge to tow for our recent test loan, but our early first drive experience with the 2020 Sierra HD in Wyoming impressed us with how smooth shift quality is in Tow/Haul mode when pulling trailers. It's not just how it shifts when towing, though. The software also does an excellent job of choosing when to upshift or downshift to maintain a steady speed for the conditions.

GMC is the segment's only HD truck maker using an independent front suspension, and it shows. The ride is compliant, and there's little chatter from the back end as well across broken roads and bumpy trails. The 2500HD is also responsive and easy to maneuver, relative to its size and heft. You're definitely driving a big truck, but GMC has done a great job at keeping what can be a brute of a truck civilized when it needs to be.

Towing is the 2500HD's specialty, and it does it with almost frightening ease, making it easy to forget you're pulling something with serious weight. Pulling out to overtake slow traffic requires little effort from the engine, even at maximum weight, and toggling the exhaust brake function helps to tax the brakes less and keep them cool in hill country. Add in GMC's ProGrade Trailering system with its 15 cameras and invisible trailer mode, and the stress evaporates out of hauling.

The AT4 trim level doesn't add a lift to the suspension and specialist tires as it does on the Sierra 1500. However, 18-inch wheels with all-terrain tires and a two-speed transfer case take care of traction while off-road suspension adds to the 2500HD's agility and stability in the rough stuff. The sheer length of the truck isn't ideal for treacherously bumpy ground, but the AT4 package gives the truck a whole new dimension. We spent a happy afternoon in California's badlands roaming around steep and slippery and rutted dirt tracks with the only concern being the width of the truck.

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.

This is the biggest downside to the Sierra in HD guise. At the end of our week with the truck, without towing anything but spending some time off-road, we logged in at 12.1 mpg with the diesel engine at the end of the week.

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 disappoint. 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.

There's no better way to describe the interior of any 2500HD model than as being cavernous. While the AT4 trim comes with bucket seats reducing seating to five, all five have plenty of room. Headroom is extensive at just over 43 inches, and only the tallest of people in the back might bang their heads going over big bumps at just shy of 39.9 inches. Up at the front, everyone gets 44.53 inches of legroom. The double cab then gives rear occupants 35.24 inches of legroom, while in the crew cab, there are 43.4 inches to stretch out into.

GMC expects people to spend a lot of time in the cabs, so the seats are well-padded and adjustable. For this year, the seating position has gotten taller along with the truck's ride height. That helps the driver get great visibility all around the cab, which becomes critical in a truck of this size. In our AT4 trim tester, the driver gets a 10-way power seat with adjustable power lumbar support as standard.

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.

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. The revisions for 2020 also mean the load height is an inch lower, making it easier to load large items.

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.

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. The SLE trim adds cruise control, power windows, and remote keyless entry while 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 head-up driver display, a power-sliding rear window, wireless charging, and ventilation for the front seats.

One of the disappointments in GMC's premium truck offering is the infotainment system's screen size, measuring just eight inches and looking even smaller in its roomy setting. However, while we would prefer a larger screen in a premium truck, the screen quality is great with the cameras, and the system is responsive and easy to navigate. Base models come with a six-speaker sound system, Bluetooth, Apple CarPlay, and Android Auto. Still, they can be upgraded via options, trims, or packages, to a Bose seven-speaker system as well as adding navigation, HD Radio, satellite radio, a mobile hotspot, wireless charging, and an infotainment system for the rear. There's even the option for a tailgate-mounted sound system by Kicker, for when you want to take the party outside.

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 two recalls already - if the seat belt pretensioners deploy, there is a chance that escaping hot gas could ignite interior materials, while in some vehicles, the hood may open unexpectedly while driving.

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.

The Sierra 2500HD has yet to be evaluated for crash safety by local authorities including the NHTSA and IIHS. Promisingly, the IIHS awarded the 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.

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, as well as active safety features made standard at a lower price point.

For anyone in the business of pulling or carrying large loads, the 2500HD is an excellent premium choice. While we know GMC can do better with an interior, the technology gets us over that. The 2500HD can quickly get pricey, and GMC understands that and banks on people choosing higher trims, options, and packages to get exactly what they want and need. It's a good approach as, at its base level, the 2500HD is a more than capable platform for heavy-duty use and has a strong and powerful drivetrain. Start upgrading it, and it becomes an impressive tool for any job someone could need a heavy-duty truck for before moving up to a dually. But we're not sure if it's a class leader, and while the strong diesel engine and clever trailer camera system are wonderful, we can't help feel that the Ram 2500 remains the unbeaten benchmark in the segment.

The cheapest model in the range is the base Sierra Regular Cab 2WD which carries an MSRP of $35,800. Next is the slightly less basic SLE at $40,400. The mid-range SLT costs $51,000 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 $58,300, followed by the range-topping Denali at $64,300. 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 $74,250 excluding the destination charge.

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, and single-zone climate control.

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.

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.

GMC doesn't expect the bulk of its sales to be in the base models, and we would be looking at non-premium trucks instead of a stripped-down Sierra model. The SLE is where we would start, and add the SLE Convenience Package for some extra creature comforts. We would also add the Technology Package - after all, if you're spending the money on a premium truck, then you'll need those premium features. For those towing sizeable loads, the ProGrade trailering system for $710 is something we consider an essential part of the 2500HD.

The Denali trim is where we back off. For a luxury trim level, the Denali's interior feels like a token effort. GMC is working on spinning Denali into a full-on luxury brand of its own, and, after seeing what GMC did with the Yukon Denali recently, we would hold off a year and see how the company develops the truck interiors.

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 MultiPro 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.

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 $1,200 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 MultiPro tailgate is a great feature, but is it worth the $1,200 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.