2020 GMC Sierra 1500 first drive review: Diesel power and upgraded tech

A new diesel engine option and some small but meaningful improvements make GMC's light-duty pickup a star.

Emme Hall Former editor for CNET Cars
I love two-seater, RWD convertibles and own a 2004 Mazdaspeed Miata for pavement fun and a lifted 2001 Miata for pre-running. I race air-cooled Volkswagens in desert races like the Mint 400 and the Baja 1000. I have won the Rebelle Rally, seven-day navigational challenge, twice and I am the only driver to compete in an EV, the Rivian R1T.
Emme Hall
5 min read

It's a good time to be a diesel pickup fan. There are more diesel-powered full-size truck options than ever before, the latest of which is the 2020 GMC Sierra 1500 . This powerful, efficient engine is just one of a host of updates GMC is giving its bread-and-butter pickup truck this year.

Let's start with the diesel engine. It's the same 3.0-liter inline-six you'll find in the 2020 Chevrolet Silverado, putting out 277 horsepower and 460 pound-feet of torque. With this engine under the hood, the GMC Sierra can tow a maximum of 9,100 pounds or haul 1,830 pounds of payload. Curiously, those specs are lower than a Chevy Silverado with the same engine. What's more, the diesel-powered versions of the and can both out-tow the GM twins, able to pull 11,400 and 12,560 pounds, respectively.

2020 GMC Sierra 1500
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2020 GMC Sierra 1500

Have diesel, will tow.


Keep it light

When asked why the tow rating is so low, GMC says its research shows that when customers want to tow more than 10,000 pounds, they generally move up to a heavy-duty truck, so the company focused on fuel economy instead. GMC says the Sierra diesel will get 30 miles per gallon on the highway, matching the Ford F-150 Power Stroke's EPA numbers. Ram hasn't released fuel economy numbers for the 1500 EcoDiesel yet, but we're expecting figures around the 30 mpg mark for this truck, as well.

Towing an 8,000 pound, 24-foot trailer up and down a 6% grade at an elevation of 6,000 feet -- not an easy task -- the diesel performs like a champ. Acceleration is more than ample, both when pulling out into traffic from a standstill and while climbing the relatively steep hill. The Sierra's 10-speed automatic transmission does its thing in the background and steps down quickly when a downshift is required. The integrated exhaust brake makes stopping easy, too, saving brake force on the steep downhill section of my drive.

Like its heavy-duty counterpart, the gets six cameras -- eight if you opt for the accessory cameras -- giving drivers no fewer than 15 views around the truck and trailer. The blind-spot monitoring system doesn't cover the length of the trailer, but when you've got all these views, who really needs it? The best bit of tech is GM's super-cool transparent trailer feature, which stitches together the view from the rear accessory camera with the tailgate-mounted camera. It's great to be able to see what's behind me and makes towing much less of a chore.

As on the Sierra HD, the light-duty 1500 features trailering apps both in the vehicle and for your phone. Test the lights, check trailer tire pressures and temperatures, and get a predeparture checklist, all in one place.

2020 GMC Sierra HD
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2020 GMC Sierra HD

All other trailer tech can go home. GMC wins with the transparent trailer view.


GMC offers the diesel engine in a few Sierra 1500 trims, one of which is the off-road-focused AT4. This model gets a 2-inch suspension lift over the standard Sierra, as well as a few goodies like skid plates and specially tuned Rancho shocks. Low-end torque, an electronic rear differential locker and meaty Goodyear Wrangler tires help it scamper up a tower of rocks fairly easily, and the truck shows it has a modicum of flex in the chassis. However, the tires aren't quite aggressive enough when the dirt gets wet. If mud is your thing, you should definitely upgrade.

Then there's the excellent carbon-fiber bed. Dubbed CarbonPro, it's part of the bed itself, not a bed liner. Not only does this save 60 pounds, but GMC let me whack it with a baseball bat as much as I wanted to test its strength; I eventually bent the bat. The CarbonPro bed has two extra tie-downs in the front as well as wheel chocks carved in for your bike or motorcycle. Three tie-downs in each corner round out the functionality of this super-functional bed.

Tech upgrades

My biggest problem with the 2019 Sierra was the lack of adaptive cruise control, so thankfully, it's been added for 2020. There are a few tech bonuses that you'll find nowhere but the Sierra, however. I love the rear camera mirror that shows a wide angle of what's behind me from the tailgate. And a new multicolor head-up display shows navigation directions and the like while the 8-inch infotainment screen focuses on trailer views.

Of course, let's not forget the awesome, six-way MultiPro tailgate. It works like a traditional tailgate, a step, a workspace, a load stop and it even has a drop-down section so I can load up the bed easier. Heck, it's even got a Kicker audio system. No other tailgate in the pickup truck class is this functional.

Another 2020 model year update is the expansion of the Elevation trim to the Crew Cab body style. Previously only available as a Double Cab, this is the trim to get if you want to leave all the horrible GMC chrome behind. Featuring a black grille, mirrors and 20-inch wheels, it just looks more aggressive than other trims, and is definitely the version of the Sierra I'd most eagerly drive home.

2020 GMC Sierra 1500: Making work look good

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The only bummer about the Sierra is its interior. It's perfectly serviceable, but that's about it. The Ram 1500 is much more luxurious, with a bigger helping of available infotainment technology. Heck, even the Ford F-150, the bastion of basic, has a nicer interior. Even the -- which is not an inexpensive truck -- feels ho-hum and outdated inside.

The final say

The base 2020 GMC Sierra starts at $29,600, plus $1,595 for destination. Most folks will upgrade to at least a midlevel SLE, which starts at $37,800. The off-road AT4 comes in at $51,000 and the fancy-pants comes in at $54,700.

The 2019 GMC Sierra was a perfectly good truck that lacked some tech and interior refinement. The 2020 model adds efficient diesel power and ups the tech game, but the cabin still leaves a lot to be desired. Still, with its unique tailgate option and myriad models to choose from, the 2020 Sierra is better poised to compete for full-size pickup shoppers' money.

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