2020 GMC Sierra 2500HD

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

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.

Read in this review:

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2020 GMC Sierra 2500HD Changes: What’s The Difference vs The 2019 Sierra 2500HD?

As a completely redesigned model, GMC has made a number of changes to the fourth-generation 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

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2020 GMC Sierra 2500HD Trims

See trim levels and configurations:

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

2020 Sierra 2500HD Exterior

2020 GMC Sierra 2500HD Front View CarBuzz
2020 GMC Sierra 2500HD Rear View CarBuzz
2020 GMC Sierra 2500HD Frontal Aspect CarBuzz
See All 2020 GMC Sierra 2500HD Exterior Photos


  • Length 250.1 in
  • Wheelbase 158.9 in
  • Height 79.8 in
  • Max Width 81.9 in

2020 Sierra 2500HD Performance

2020 GMC Sierra 2500HD Frontal Aspect 1 CarBuzz
2020 GMC Sierra 2500HD Aft View CarBuzz
2020 GMC Sierra 2500HD Motor CarBuzz

Engine and Transmission

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

Handling and Driving Impressions

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.

2020 Sierra 2500HD Interior

2020 GMC Sierra 2500HD Dashboard CarBuzz
2020 GMC Sierra 2500HD Climate Control CarBuzz
2020 GMC Sierra 2500HD Armrest CarBuzz
See All 2020 GMC Sierra 2500HD Interior Photos

Seating and Interior Space

  • Seating capacity
  • Front Leg Room 44.5 in
  • Front Head Room 43.0 in
  • Rear Leg Room 43.4 in
  • Rear Head Room 39.9 in

2020 Sierra 2500HD Trunk and Cargo Space

2020 GMC Sierra 2500HD Rearmost Seats CarBuzz
2020 GMC Sierra 2500HD Cup Holder CarBuzz
2020 GMC Sierra 2500HD Cargo Capacity CarBuzz

2020 Sierra 2500HD Safety and Reliability


  • 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

US NHTSA Crash Test Result

NHTSA safety ratings are not available at this time.

Verdict: Is the 2020 GMC Sierra 2500HD A Good Truck?

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.

2020 GMC Sierra 2500HD Comparisons

GMC Sierra 1500 CarBuzz
Chevrolet Silverado 2500HD Chevrolet
CompetitorHorsepowerMPGPrice (MSRP)
GMC Sierra 2500HD401 hpTBC$42,200
GMC Sierra 1500 310 hp19/22 mpg$37,100
Chevrolet Silverado 2500HD 401 hpTBC$39,500

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 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.

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 $1,200 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.

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