2020 GMC Sierra 1500

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The Car Connection Expert Review

Aaron Cole Aaron Cole Managing Editor
December 16, 2019

Buying tip

The 2020 Sierra 1500 is best in SLT and Denali guise; they’re luxury trucks and fitted accordingly.

features & specs

2WD Crew Cab 147"
2WD Crew Cab 147" Denali
2WD Crew Cab 147" Elevation
16 city / 21 hwy
17 city / 23 hwy
20 city / 23 hwy

The 2020 GMC Sierra 1500 draws from a broad palette to paint a handsome, conservatively styled truck.

The 2020 GMC Sierra 1500 finds new ways to deliver on an automotive concept older than a century: the pickup truck.

This year, the GMC adds to its roster a turbodiesel inline-6 that’s more refined, new trailer cameras, and a handful of added trim levels. 

The 2020 Sierra gets a 5.3 out of 10. (Read more about how we rate cars.)

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The lineup for the GMC Sierra 1500 is wide and deep; pack sunscreen and a snack. The 2020 Sierra 1500 is available in base, SLE, SLT, Elevation, AT4, and Denali versions. Five engines, three transmissions, and two driveline configurations complement three cab options, three bed options, and endless options. In short: the GMC Sierra 1500 can be any flavor you like. Work trucks cost just over $30,000, while fully loaded Sierra 1500 Denalis crest $60,000 before options.

Regardless of what’s underhood or on the badges, the Sierra 1500 looks the part. It was restyled last year and it’s the smarter look compared to the mechanically related Chevy Silverado 1500. 

The body sides are flat and without flair, but the GMC’s grille is the right side of conservative. 

Inside, the truck gets more comfortable and colorful with more money, but all versions prioritize capability and ease of use over frippery style. 

Base Sierra 1500s get a 285-horsepower 4.3-liter V-6 that’s mostly work-spec—few trucks will be parked in driveways with the base engine. 

A 2.7-liter turbo-4 is more common among retail buyers and it’s more powerful at 310 hp. It’s hooked to an 8-speed automatic and rear- or four-wheel drive. It rates up to 21 mpg combined, and it’s acceptable for around-town duty. The turbo-4 becomes thirstier as it lugs more, and its less refined than the other powertrains. 

A 5.3-liter V-8 with 355 hp is our sweet spot, and gets a new 10-speed automatic when equipped with four-wheel drive in certain trims. It’s more powerful off the line and can lug more than 11,000 pounds. 

A 420-hp 6.2-liter V-8 is the top powertrain and is only available with four-wheel drive. It manages 17 mpg combined thanks to its standard 10-speed automatic, but tapping into its deep wells of power similarly drains the tank quicker. 

A 3.0-liter turbodiesel inline-6 joins the crowd this year and its 277 hp is just enough, but it’s the quietest and likely the most efficient. Its trick isn’t towing—just 9,000 pounds—but it’s the smoothest of the bunch. 

Regular-, extended-, and crew-cab models are available with 5-foot-8-inch, 6-foot-6, or 8-foot bed lengths, depending on configuration. 

The four-door crew cab is a family vehicle, there’s more leg room in the rear than before. Regardless of cab or bed length, the Sierra 1500 is a full-size pickup—measure your garage. 

Safety isn’t one of the Sierra 1500’s best looks. GM unwisely keeps automatic emergency braking from base versions. It’s available on top trims as an option, which is a head-scratcher ahead of next year’s near-mandate for the life-saving tech on all cars. 

Base Sierras get power features, air conditioning, Bluetooth connectivity, a USB port, 17-inch wheels, and Apple CarPlay- and Android Auto-compatible infotainment with a 7.0-inch touchscreen.

We find better features and value in Sierra 1500 SLTs that get an 8.0-inch touchscreen for infotainment, 18-inch wheels, automatic climate control, power-adjustable driver’s seat, leather upholstery, a trick tailgate that opens six different ways, and a high-definition rearview camera.


2020 GMC Sierra 1500


The 2020 Sierra 1500 takes few risks in the way it looks.

The new Sierra 1500 is right down the middle among pickups and it’s right down the middle on our rating scale. It’s a blend of simple lines and straight edges without many rounded corners or much room for flair. It’s a 5.

The GMC Sierra 1500 is less expressive than the related Chevy Silverado—we like that. The Sierra 1500’s tall grille cuts between C-shaped headlights and meets up with a lower front bumper that gives it a square-jaw look. The amount of chrome varies between the pickup’s range: Sierra Denalis wear the most chrome, off-road models get butch-looking accents. 

Down the Sierra’s body, thin gray plastic wraps around the wheel wells to cut down on visual weight. Crew-cab models, which are the most popular, get a rear-window kick up that breaks out of the straight-sided look—albeit briefly. 

The rear tailgate wears a big GMC or Denali badge, depending on model, and C-shaped taillights bookend the sides. It’s upright and blocky, although not especially groundbreaking. 

Inside, the Sierra 1500 is just as horizontal and wears dressier shades by throwing more money at it. A massive shield-shaped panel ropes off most of the center stack of controls for audio and climate. 

Most pickups get an 8.0-inch touchscreen for infotainment (base models make do with a 7.0-inch unit). The Denali trucks feature leather everywhere, wood and aluminum accents, fitting for its price tag that starts at more than $61,000. 

Review continues below

2020 GMC Sierra 1500


The Sierra 1500 loses the numbers game in some configurations, but it also saves our backs in other versions.

The 2020 Sierra 1500’s performance story gets longer this year thanks to the arrival of a new turbodiesel engine. 

That brings the number of available engines to five, the number of transmissions to three, two driveline configurations, and a partridge in a pear tree. 

We give the Sierra 1500 two points above average for its stout V-8s. The Sierra 1500 Denali’s ride is silky thanks to its adaptive dampers and we’d give it that point if we rated it separately. The Sierra 1500 is a 7 for now.

The engine lineup consists of 4-, 6-, or 8-cylinder power. The base 4.3-liter V-6 is found only on base trucks that are best for work detail, not many retail buyers will opt for that engine. The V-6 makes 285 hp and 305 lb-ft of torque and it shifts power through a 6-speed automatic. Its best trick is its low price for fleet operators. 

The next step up is a step down in cylinders. A 2.7-liter turbo-4 makes 310 hp and 348 lb-ft sent to the rear or all four wheels via an 8-speed automatic. Efficiency is the turbo-4’s best look and it’s how the big Sierra 1500 can manage up to 21 mpg combined, according to the EPA. We’ve driven the turbo-4 and found that what it gains in efficiency it gives up in drivability. The turbo-4 is rated to tow up to 6,800 pounds, although its consumption increases dramatically if you do. The turbos stay in the picture too long, gulping down air and fuel to drag the Sierra 1500 and its load properly. 

For those who tow frequently, there are better options. We’d start with the 5.3-liter V-8 that rates at 355 hp and 383 lb-ft. It’s paired with a 10-speed automatic in SLT, AT4, and Denali models with four-wheel drive and its rated to tow up to 11,300 pounds in certain configurations. The V-8 burbles happily off the line and pulls well at just about any speed. We think many drivers would be satisfied with the 5.3-liter V-8. 

But if restraint isn’t your thing, a 6.2-liter V-8 is available in SLT, AT4, and Denali trucks that’s the peak of power and consumption. It rates at 420 hp and 460 lb-ft and shifts through a 10-speed automatic. Thanks to a few extra cogs, the EPA rates the 6.2-liter V-8 at 17 mpg combined, but deep stabs at the throttle can erase those gains in a hurry. The 6.2-liter V-8 is equipped only with four-wheel drive and GMC says it can pull up to 12,000 pounds when properly equipped. We believe them, too. The 6.2-liter V-8 is stout and convincing. Our only gripe is that with an unladen bed the motor can almost push too much power to the rear wheels, hopping the suspension around at city speeds. 

A 3.0-liter turbodiesel is finally here for 2020, and it slots in somewhere between the turbo-4 and 5.3-liter for capability and efficiency. The turbodiesel spins out just 277 hp, but it makes 460 lb-ft—same as the 6.2-liter V-8. The 3.0-liter inline-6 turbodiesel is the most refined of the bunch, and the quietest, and the thriftiest at about 34 mpg on the highway in our initial tests. The bad news? It’s more expensive than the 2.7-liter turbo-4 and the 5.3-liter V-8 and tows up to 9,000 pounds. Over the long life of a truck, owners that often tow may recoup the cost of the turbodiesel, but it’ll take a while. 

Most trucks are fitted with coil-over shocks in the front and leaf springs in the rear, although Denali trucks can get adaptive dampers. The Sierra 1500 wears 17- to 22-inch wheels, depending on trim level and ride quality improves or suffers accordingling. 

We’ve driven mostly Sierra 1500 Denalis, and GMC estimates nearly half of retail buyers will opt for those tricks. 

The big 22-inch wheels on Sierra 1500 Denalis throw more force back into the cabin, which is calmed by the adaptive valving in the uprated dampers. It’s calming, but we’d prefer the 20-inch tires to max out on ride quality. 

Every Sierra 1500 steers well, and the GMC is less jouncy than an F-150 and more compliant than Ram 1500s fitted with its optional air suspension. 

Review continues below

2020 GMC Sierra 1500

Comfort & Quality

Comfort and cargo are two reasons to consider the 2020 Sierra 1500.

Comfort and utility are the 2020 Sierra 1500’s best features, and it delivers both by the truckload. (See what we did there?) 

The GMC is a 7 for comfort thanks to its spacious interior and cargo capabilities.

The Sierra 1500 is equipped with a 5-foot-8-inch, 6-foot-6, or 8-foot bed, depending on cab configuration. Regular cabs are two-door affairs, while extended- and crew-cab models offer seats for four. The crew cab is a four-door, five-adult vehicle that most shoppers will pick and it’s our pick for comfort and stretch-out space. 

Front passengers have it good, but rear-seat riders have it better. The rear bench can fit three across and the outboard seats can be heated as an optional extra. The rear seats don’t recline, but there is more head room than in older GMC trucks and long legs fit better thanks to more leg room by three inches. 

The Sierra 1500’s interior storage is a gem, too. The big center console on top trucks can swallow laptops and tools, file folders and pencils, and it offers multiple USB charge ports for devices. Generous sound-deadening material in the Sierra 1500 helps keep the pickup’s interior, which can be trimmed in luxury materials, quiet and serene. 

GMC Sierra 1500 utility

The Sierra 1500’s bed is deeper and wider than before, GMC says it’s more spacious by 20 percent over prior generations of the pickup. Depending on bed configuration, GMC offers up to a dozen tie-downs in the bed, bed steps at the corners, movable tie-downs, a multifunction tailgate with different ways to open, and in-bed LED lights. 

If that’s not enough, GMC offers a carbon-fiber bed that saves about 60 pounds, but it’s only offered in four-door crew-cab models with a standard-length bed.

Like you’d expect in anything with an open bed, the Sierra 1500 can carry more than its fair share of cargo and gear, more than 2,200 pounds in some configurations. Expect plenty of people to ask if you can help move on the weekends.

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2020 GMC Sierra 1500


The GMC Sierra 1500 lags others in official safety scores.

In many ways, the 2020 Sierra 1500 is ahead of the curve, but for safety, it’s well behind. 

Federal testers gave the pickup a four-star overall score, and the IIHS gave it a “Marginal” rating for passenger-side small-overlap crash protection. Base pickups skip automatic emergency braking again, and we land at a 2 for safety.

This may well be the last year GMC will get that last demerit, nearly every new car starting next year will get automatic emergency braking as standard equipment. For now, GMC walls that off to more expensive trims. 

The good news? There are multiple camera angles to shimmy the truck into parking spaces and trailer hitches, which mitigates the big body bestowed to the pickup. Also, the IIHS gave the Sierra 1500 top “Good” scores in all crash tests, except the passenger-side small-overlap test. When equipped with the optional automatic emergency braking system, the Sierra 1500 avoided front crashes at 12 and 25 mph. 

Every headlight configuration was rated “Poor” by the IIHS, which noted that illumination for all versions was fair to poor. 

We’ll update this space if those scores change. 


2020 GMC Sierra 1500


The 2020 Sierra 1500 can be a luxury truck with few rivals.

Pickup trucks are some of the most configurable vehicles on the planet. With multiple options for trims, powertrains, cabs, beds, and creature comforts, no two pickups need to leave the factory with identical features—and that’s before we’ve even talked colors. 

Starting from an average score, the 2020 Sierra 1500 gets a point for good infotainment and another for a bevy of options. It’s a 7 here.

We value your time, so what follows is the Readers’ Digest version of the 2020 Sierra 1500. 

The 2020 GMC Sierra is available in base, SLE, Elevation, SLT, AT4, and Denali roster. Every truck gets power features, air conditioning, Bluetooth connectivity, a USB port, 17-inch wheels, and Apple CarPlay- and Android Auto-compatible infotainment with a 7.0-inch touchscreen. Base trucks are for work detail, and we imagine more shoppers will find better value in the Sierra 1500 SLT, which adds more comfort features. 

The SLT adds an 8.0-inch touchscreen for infotainment, 18-inch wheels, automatic climate control, power-adjustable driver’s seat, leather upholstery, a trick tailgate that opens six different ways, and a high-definition rearview camera. Cooled front seats, navigation, wireless smartphone chargers, heated rear seats, towing and trailering packages are optional extras. 

GMC’s longtime ace has been its Denali-trimmed trucks, which are comfortable, powerful, luxurious—and also expensive. 

The Denali trucks heap on standard features such as comfortable front bucket seats, adaptive suspension, open-pore wood trim, navigation, 22-inch wheels, a surround-view camera system, chrome, and a rear camera mirror. 

The AT4 trim level is geared for off-roaders with a 2-inch suspension lift, chunkier tires, tougher hardware; the Elevation doesn’t go as far but offers more rugged bits than most of the lineup.

Tow much? GMC offers a trailer view system with more cameras than a local bank—15 different views are available. A carbon fiber-composite bed is on the options list, and it’s pricey, but gives the GMC truck bragging rights over its competitors. 

Review continues below

2020 GMC Sierra 1500

Fuel Economy

Turbodiesels do swell, but most Sierras earn about 20 mpg combined.

The EPA pegs the newest GMC Sierra drivetrain as its most efficient. The new 3.0-liter turbodiesel earns EPA ratings of 23 mpg city, 30 highway, 26 combined in rear-drive form; with four-wheel drive, it slips to 22/26/24 mpg.

The 5.3-liter V-8 is still the most common engine in the Sierra; it's rated at 17/24/20 mpg with rear-wheel drive, and 16/19/22 mpg with four-wheel drive and an 8-speed automatic.

The big 6.2-liter V-8 is still around, and thanks to its 10-speed automatic it rates 15/20/17 mpg, about the same as Sierras with the base V-6. It's rated for premium fuel, however.

GMC offers a turbo-4 that was last year’s efficiency champ; most configurations are rated at 19/22/20 mpg. 

Review continues below
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Comfort & Quality 7
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