GMC specifications

GMC Sierra specifications and photos

The 2021 GMC Sierra is the restyled fifth generation of this full-size pickup truck. Available in both rear-wheel and four-wheel drive configurations, it offers heavy-duty utility paired with an extensive list of technological updates.

Years 2021
Body type pickup
Trims 9
Photos 16
Front three-quarter view of a white 2021 GMC Sierra pickup parked on an open coastal dock
Overview

GMC Sierra at a glance

Quick model context before comparing photos and trim-level specifications.

Introduced in late 2021, the updated fifth-generation GMC Sierra received a significant overhaul focused on its interior and technology offerings. The lineup caters to a wide spectrum of truck buyers, from commercial operators needing basic towing setups to luxury buyers looking for premium finishes. In May 2023, the manufacturer further expanded the range by introducing the off-road-oriented AT4X and AEV Edition trims. Measuring nearly 5.9 meters in length, the Sierra maintains a massive footprint, ensuring strong cargo volume and cabin space for up to five passengers.

  • Power: 281-426 hp
  • Engine displacement: 2727-6162 cc
  • Transmissions: 10-speed automatic, 8-speed automatic
  • Seating: 5 seats
Research hub

Photos, trims and specifications for GMC Sierra

This model page brings gallery images, trim comparison, and detailed technical data together for the 2021 generation.

Open photo gallery 16 images Compare trims 9 configurations View detailed specs 2727-6162 cc Explore related pages GMC and similar models
Running costs

Estimate fuel cost

Use trim-level fuel consumption data to estimate monthly and yearly fuel spending.

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Monthly cost -
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Fuel costs are estimates. Real consumption can change with driving style, traffic, tires, weather, load, and market-specific equipment.

Model guide

GMC Sierra overview

Editorial context for design, cabin, performance, practicality, and buyer notes.

Design

The Sierra presents a classic, imposing full-size truck profile, measuring 5,891 mm in length, 2,063 mm in width, and 1,918 mm in height. The exterior design varies greatly by trim level. The flagship Denali Ultimate trim features dark styling elements and large 22-inch wheels. Meanwhile, the AT4X is built for trail use and features a modified suspension system to tackle rough terrain. The standard ground clearance across most configurations sits at 205 mm.

Interior

GMC significantly upgraded the Sierra's cabin for the restyled model, pushing it closer to the premium segment. High-end configurations feature natural wood trim, premium leather seating, and a Bose audio system. The dashboard is dominated by a 13.4-inch multimedia display that supports Apple CarPlay and Android Auto, paired with a 12.3-inch digital instrument cluster. Drivers also benefit from an available 15-inch head-up display, ensuring critical vehicle information is easily visible without looking down.

Performance

The powertrain lineup is extensive. Buyers can choose a 2.7-liter turbocharged four-cylinder producing 313 horsepower and 569 Nm of torque, or opt for traditional V8 power: a 5.3-liter (360 hp, 519 Nm) and a 6.2-liter (426 hp, 623 Nm). A 3.0-liter Duramax turbodiesel is also available, delivering 281 hp and 624 Nm of torque. Transmissions include an 8-speed automatic on select base models and a 10-speed automatic on higher trims. Both rear-wheel and four-wheel drive systems are offered.

Practicality

Built on a sturdy 3,745 mm wheelbase, the Sierra is designed for maximum utility. It serves comfortably as a daily family vehicle with its spacious five-seat cabin, while retaining serious work capability. The 3.0-liter turbodiesel engine is particularly notable for heavy duty tasks, increasing the truck's maximum towing capacity to an impressive 6,000 kg.

Safety and tech

The updated Sierra is equipped with modern driver assistance technology. In addition to the large digital displays and HUD, the top-tier Denali Ultimate trim introduces Super Cruise. This advanced semi-autonomous driving system operates as a hands-free highway assistant, significantly reducing driver fatigue on long trips.

Buyer notes

When selecting a GMC Sierra, buyers should carefully match the powertrain to their primary usage. The 2.7L turbo provides a modern alternative to base V8s, while the diesel is the clear choice for frequent, heavy towing. Ensure you verify the transmission type, as the preferred 10-speed automatic is not standard on every trim. Buyers prioritizing off-road performance should look directly at the AT4X.

Configurations

Trims and key specifications

Use this table to compare the main differences between available configurations.

Power 281-426 hp
Engine displacement 2727-6162 cc
Seating 5 seats
Transmissions 10-speed automatic, 8-speed automatic
Trim / modification Engine Power Seats Transmission
5.3i (360 hp) 10-speed automatic 5328 cc 360 hp 5 10-speed automatic
5.3i (360 hp) 10-speed automatic 4x4 5328 cc 360 hp 5 10-speed automatic
6.2i (426 hp) 10-speed automatic 4x4 6162 cc 426 hp 5 10-speed automatic
2.7i (313 hp) 8-speed automatic 2727 cc 313 hp 5 8-speed automatic
2.7i (313 hp) 8-speed automatic 4x4 2727 cc 313 hp 5 8-speed automatic
2.7i (313 hp) 10-speed automatic 2727 cc 313 hp 5 10-speed automatic
2.7i (313 hp) 10-speed automatic 4x4 2727 cc 313 hp 5 10-speed automatic
3.0 Duramax (281 hp) 10-speed automatic 2999 cc 281 hp 5 10-speed automatic
3.0 Duramax (281 hp) 10-speed automatic 4x4 2999 cc 281 hp 5 10-speed automatic

Specifications can vary by market, model year, and equipment package. Use the trim sections below to review the full data for each configuration.

Detailed specs

Specifications by trim

Choose a configuration below to open full technical data grouped by category.

5.3i (360 hp) 10-speed automatic 5.3i (360 hp) 10-speed automatic 4x4 6.2i (426 hp) 10-speed automatic 4x4 2.7i (313 hp) 8-speed automatic 2.7i (313 hp) 8-speed automatic 4x4 2.7i (313 hp) 10-speed automatic 2.7i (313 hp) 10-speed automatic 4x4 3.0 Duramax (281 hp) 10-speed automatic 3.0 Duramax (281 hp) 10-speed automatic 4x4
5.3i (360 hp) 10-speed automatic 31 specifications

Specifications

Performance and consumption

Fuel consumption city, L/100 km 14.3
Fuel consumption highway, L/100 km 11.2
Fuel consumption combined, L/100 km 13.2

Engine

Engine 5.3i
Engine code L83/L8B
Engine type Internal combustion engine
Fuel type Gasoline
Engine displacement, cc 5328
Cylinder layout V-type
Number of cylinders 8
Valves 16
Compression ratio 11.0:1
Power, hp 360
RPM at max power 5600
Torque, Nm 519
RPM at max torque 4100

Dimensions

Seats 5
Length, mm 5891
Width, mm 2063
Height, mm 1918
Wheelbase, mm 3745
Kerb weight, kg 2190
Fuel tank capacity, L 91
Ground clearance, mm 205

Transmission and drive

Transmission 10-speed automatic
Transmission type automatic
Drive Rear-wheel drive
Number of gears 10
Transmission manufacturer GM
Automatic transmission +
Transmission country USA
5.3i (360 hp) 10-speed automatic 4x4 31 specifications

Specifications

Performance and consumption

Fuel consumption city, L/100 km 14.8
Fuel consumption highway, L/100 km 11.2
Fuel consumption combined, L/100 km 13

Engine

Engine 5.3i
Engine code L83/L8B
Engine type Internal combustion engine
Fuel type Gasoline
Engine displacement, cc 5328
Cylinder layout V-type
Number of cylinders 8
Valves 16
Compression ratio 11.0:1
Power, hp 360
RPM at max power 5600
Torque, Nm 519
RPM at max torque 4100

Dimensions

Seats 5
Length, mm 5891
Width, mm 2063
Height, mm 1918
Wheelbase, mm 3745
Kerb weight, kg 2190
Fuel tank capacity, L 91
Ground clearance, mm 205

Transmission and drive

Transmission 10-speed automatic
Transmission type automatic
Drive All-wheel drive
Number of gears 10
Transmission manufacturer GM
Automatic transmission +
Transmission country USA
6.2i (426 hp) 10-speed automatic 4x4 28 specifications

Specifications

Engine

Engine 6.2i
Engine code L86
Engine type Internal combustion engine
Fuel type Gasoline
Engine displacement, cc 6162
Cylinder layout V-type
Number of cylinders 8
Valves 16
Compression ratio 11.5:1
Power, hp 426
RPM at max power 5600
Torque, Nm 623
RPM at max torque 4100

Dimensions

Seats 5
Length, mm 5891
Width, mm 2063
Height, mm 1918
Wheelbase, mm 3745
Kerb weight, kg 2190
Fuel tank capacity, L 91
Ground clearance, mm 205

Transmission and drive

Transmission 10-speed automatic
Transmission type automatic
Drive All-wheel drive
Number of gears 10
Transmission manufacturer GM
Automatic transmission +
Transmission country USA
2.7i (313 hp) 8-speed automatic 31 specifications

Specifications

Performance and consumption

Fuel consumption city, L/100 km 12.9
Fuel consumption highway, L/100 km 11
Fuel consumption combined, L/100 km 11.5

Engine

Engine 2.7i
Engine code L3B
Engine type Internal combustion engine
Fuel type Gasoline
Engine displacement, cc 2727
Cylinder layout Inline
Number of cylinders 4
Valves 16
Turbocharger +
Power, hp 313
RPM at max power 5600
Torque, Nm 569
RPM at max torque 1500

Dimensions

Seats 5
Length, mm 5891
Width, mm 2063
Height, mm 1918
Wheelbase, mm 3745
Kerb weight, kg 2190
Fuel tank capacity, L 91
Ground clearance, mm 205

Transmission and drive

Transmission 8-speed automatic
Transmission type automatic
Drive Rear-wheel drive
Number of gears 8
Transmission manufacturer GM
Automatic transmission +
Transmission country USA
2.7i (313 hp) 8-speed automatic 4x4 31 specifications

Specifications

Performance and consumption

Fuel consumption city, L/100 km 13.1
Fuel consumption highway, L/100 km 11.6
Fuel consumption combined, L/100 km 12.2

Engine

Engine 2.7i
Engine code L3B
Engine type Internal combustion engine
Fuel type Gasoline
Engine displacement, cc 2727
Cylinder layout Inline
Number of cylinders 4
Valves 16
Turbocharger +
Power, hp 313
RPM at max power 5600
Torque, Nm 569
RPM at max torque 1500

Dimensions

Seats 5
Length, mm 5891
Width, mm 2063
Height, mm 1918
Wheelbase, mm 3745
Kerb weight, kg 2190
Fuel tank capacity, L 91
Ground clearance, mm 205

Transmission and drive

Transmission 8-speed automatic
Transmission type automatic
Drive All-wheel drive
Number of gears 8
Transmission manufacturer GM
Automatic transmission +
Transmission country USA
2.7i (313 hp) 10-speed automatic 28 specifications

Specifications

Engine

Engine 2.7i
Engine code L3B
Engine type Internal combustion engine
Fuel type Gasoline
Engine displacement, cc 2727
Cylinder layout Inline
Number of cylinders 4
Valves 16
Turbocharger +
Power, hp 313
RPM at max power 5600
Torque, Nm 569
RPM at max torque 1500

Dimensions

Seats 5
Length, mm 5891
Width, mm 2063
Height, mm 1918
Wheelbase, mm 3745
Kerb weight, kg 2190
Fuel tank capacity, L 91
Ground clearance, mm 205

Transmission and drive

Transmission 10-speed automatic
Transmission type automatic
Drive Rear-wheel drive
Number of gears 10
Transmission manufacturer GM
Automatic transmission +
Transmission country USA
2.7i (313 hp) 10-speed automatic 4x4 28 specifications

Specifications

Engine

Engine 2.7i
Engine code L3B
Engine type Internal combustion engine
Fuel type Gasoline
Engine displacement, cc 2727
Cylinder layout Inline
Number of cylinders 4
Valves 16
Turbocharger +
Power, hp 313
RPM at max power 5600
Torque, Nm 569
RPM at max torque 1500

Dimensions

Seats 5
Length, mm 5891
Width, mm 2063
Height, mm 1918
Wheelbase, mm 3745
Kerb weight, kg 2190
Fuel tank capacity, L 91
Ground clearance, mm 205

Transmission and drive

Transmission 10-speed automatic
Transmission type automatic
Drive All-wheel drive
Number of gears 10
Transmission manufacturer GM
Automatic transmission +
Transmission country USA
3.0 Duramax (281 hp) 10-speed automatic 29 specifications

Specifications

Engine

Engine 3.0 Duramax
Engine code LM2
Engine type Internal combustion engine
Fuel type Diesel
Engine displacement, cc 2999
Cylinder layout Inline
Number of cylinders 6
Valves 24
Turbocharger +
Compression ratio 15.0:1
Power, hp 281
RPM at max power 3750
Torque, Nm 624
RPM at max torque 1500

Dimensions

Seats 5
Length, mm 5891
Width, mm 2063
Height, mm 1918
Wheelbase, mm 3745
Kerb weight, kg 2190
Fuel tank capacity, L 91
Ground clearance, mm 205

Transmission and drive

Transmission 10-speed automatic
Transmission type automatic
Drive Rear-wheel drive
Number of gears 10
Transmission manufacturer GM
Automatic transmission +
Transmission country USA
3.0 Duramax (281 hp) 10-speed automatic 4x4 29 specifications

Specifications

Engine

Engine 3.0 Duramax
Engine code LM2
Engine type Internal combustion engine
Fuel type Diesel
Engine displacement, cc 2999
Cylinder layout Inline
Number of cylinders 6
Valves 24
Turbocharger +
Compression ratio 15.0:1
Power, hp 281
RPM at max power 3750
Torque, Nm 624
RPM at max torque 1500

Dimensions

Seats 5
Length, mm 5891
Width, mm 2063
Height, mm 1918
Wheelbase, mm 3745
Kerb weight, kg 2190
Fuel tank capacity, L 91
Ground clearance, mm 205

Transmission and drive

Transmission 10-speed automatic
Transmission type automatic
Drive All-wheel drive
Number of gears 10
Transmission manufacturer GM
Automatic transmission +
Transmission country USA
FAQ

GMC Sierra questions

Short answers based on the specifications and photos available in this catalog.

What engines are available in the 2021 GMC Sierra?

The Sierra is available with a 2.7-liter turbocharged four-cylinder, a 5.3-liter V8, a 6.2-liter V8, and a 3.0-liter Duramax turbodiesel.

What is the towing capacity of the GMC Sierra diesel?

Equipped with the 3.0-liter Duramax turbodiesel engine, the GMC Sierra is capable of towing up to 6,000 kg.

Does the GMC Sierra offer hands-free driving?

Yes, the flagship Denali Ultimate trim features the Super Cruise system, which allows for hands-free driving on compatible highways.

What are the dimensions of the Sierra?

The truck is massive, measuring 5,891 mm in length, 2,063 mm in width, and 1,918 mm in height, with a ground clearance of 205 mm.

Which transmission comes with the Sierra?

Depending on the engine and trim level, the Sierra uses either an 8-speed or a 10-speed automatic transmission.