The 2021 GMC Sierra Diesel pickup truck receives minor updates to the Sierra 1500 light duty model as well as the Sierra 2500HD and 3500HD Heavy Duty models for the 2021 model year.
| Assembly Location | GM Flint Assembly in Flint, Michigan, USA and GM Fort Wayne Assembly in Fort Wayne, Indiana, USA | |
| Body Style(s) | Light-Duty, Heavy-Duty, and Medium-Duty Pickup Trucks | |
| Layout | Front-Engined, Longitudinal | |
| Engine(s) | 3.0 LM2 Duramax I6, 6.6L L5P V8 | |
| Transmission(s) | Allison 10-Speed Auto, 10-Speed Auto | |
| Drive Wheels | Rear-Wheel-Drive, Four-Wheel-Drive | |
| Availability | U.S.A., Canada, Mexico | |
| Predecessor | 2020 GMC Sierra | |
| Successor | 2022 GMC Sierra | |
Changes, Updates, New Features
2021 GMC Sierra Diesel 1500
An all-new, fourth-generation Sierra Diesel Light Duty was released for the 2019 model year. After receiving some revisions for the 2020 model year, the Sierra Diesel 1500 is again receiving a few minor changes and updates for the 2021 model year:
Exterior
- Deletion of four exterior colors
- Addition of four exterior colors
Interior
- Addition of Wireless Phone Projection
- for Apple CarPlay and Android Auto audio systems
- Addition of premium front and rear floor liners with removable carpet inserts
Packaging
- Bed View Camera is no longer available as a free flow item
- Included and only available with the Technology Package
- Deletion of Denali Premium Package
See detailed 2021 GMC Sierra 1500 changes, updates and new features here: 2021 GMC Sierra 1500 change log.
The updates and changes described here are specific to the U.S. market and may differ for other markets.
2021 GMC Sierra Diesel 2500HD & 3500HD Changes
The Sierra Heavy Duty underwent a complete overhaul (redesign and re-engineering) for the 2020 model year, though the tried and true 6.6-liter Duramax L5P turbo-diesel V8Â remains. As such, the pickup trucks have received some minor changes and updates for 2021 model year, which are as follows:
Exterior
- Deletion of two exterior color options
- Addition of three exterior color options
- Addition of power-retractable Assist steps with stainless steel accents
- Addition of 20-inch (50.8 cm) high gloss Black painted aluminum wheels (RTJ)
- Addition of Bedside Storage, right hand and left hand side
- Addition of Tie-Downs option – includes 4
- Addition of 20-inch Transit wheels for 20-inch LPO-level wheels
- Addition of 20-inch wheels with new finish, machined aluminum with high gloss Black accents (SKX)
- LPO-level item
- Addition of 20-inch (50.8 cm) multi-dimensional Chrome aluminum wheels (SKW)
- LPO-level item
- Exclusive to Denali models
Interior
- Addition of Premium floor liners with removable carpet inserts
Mechanical
- Standard tailgate is now available on SLE models, remains standard on base models, and is no longer available for SLT, AT4, or Denali models.
- Gooseneck / 5th Wheel Package is not available on Denali models
See detailed 2021 GMC Sierra HD changes, updates and new features here: 2021 GMC Sierra HD change log.
The updates and changes described here are specific to the U.S. market and may differ for other markets.
See detailed 2021 GMC Sierra Diesel changes, updates and new features here: 2021 GMC Sierra Diesel change log.
Body Styles
The 2021 GMC Sierra Diesel 1500 is available as a light-duty full-size pickup truck with several cab and bed configurations, however, Regular Cab models are not available with the turbo-diesel engine option.
Meanwhile the Sierra Diesel 2500HD and 3500HD models are available as heavy-duty full-size pickup trucks. Notably, 3500HD models are available exclusively as Crew Cab models.
Sierra 1500 Configurations
- Crew Cab, Short Box
- Crew Cab, Standard Box
- Double Cab, Standard Box
Sierra 2500HD Configurations
(all with single rear wheel)
- Regular Cab, Long Box
- Double Cab, Standard Box
- Double Cab, Long Box
- Crew Cab, Standard Box
- Crew Cab, Long Box
Sierra 3500HD Configurations
- Crew Cab, Standard Box, Single Rear Wheel
- Crew Cab, Long Box, Single Rear Wheel
- Crew Cab, Long Box, Dual Rear Wheel
Powertrain
The 2021 GMC Sierra Diesel is offered with the following turbo-diesel engine and transmission choices:
| Class | Engine | Transmission | Horsepower (HP) / Kilowatts (kW) @ RPM | Torque (lb-ft) / Newton-Meters (N-m) @ RPM | Axle |
|---|---|---|---|---|---|
| Heavy Duty | 6.6L Duramax L5P V8 | 10-Speed Automatic (MGM, MGU) | 445 / 331.97 @ 2800 | 910 / 1228.50 @ 1600 | 3.42 |
| Light Duty | 3.0L LM2 Duramax I6 | 10-Speed Automatic (MQB) | 277 / 206.64 @ 3750 | 460 /621 @ 1500 | 3.23 |
As stated, the 2021 Sierra 1500 continues to be offered in either rear-wheel or four-wheel drive configurations. Notably, General Motors made a parts change halfway through the 2020 model year, resulting in High Country 4WD models being equipped with the eight-speed automatic transmission rather than the newer ten-speed unit. To compensate for the older technology, GM is offering buyers a $200 credit.
Another noteworthy occurrence is a $1,500 price reduction, which GMAuthority was the first to report. The change results in the following starting prices for Sierra 1500 models equipped with the Duramax Diesel engine option:
| Model | Starting MSRP (before reduction) |
|---|---|
| SLE Double Cab 2WD | $45,970 |
| SLE Double Cab 4WD | $49,270 |
| SLE Crew Cab Short Box 2WD | $48,370 |
| SLE Crew Cab Short Box 4WD | $51,670 |
| SLE Crew Cab Standard Box 2WD | $48,670 |
| SLE Crew Cab Standard Box 4WD | $51,970 |
| Elevation Double Cab 2WD | $47,505 |
| Elevation Double Cab 4WD | $50,805 |
| Elevation Crew Cab Short Box 2WD | $50,130 |
| Elevation Crew Cab Short Box 4WD | $53,430 |
| Elevation Crew Cab Standard Box 2WD | $50,430 |
| Elevation Crew Cab Standard Box 4WD | $53,730 |
| SLT Double Cab 2WD | $48,590 |
| SLT Double Cab 4WD | $52,090 |
| SLT Crew Cab Short Box 2WD | $50,990 |
| SLT Crew Cab Short Box 4WD | $54,490 |
| SLT Crew Cab Standard Box 2WD | $51,290 |
| SLT Crew Cab Standard Box 4WD | $54,970 |
| AT4 Double Cab 4WD | $55,390 |
| AT4 Crew Cab Short Box 4WD | $57,790 |
| AT4 Crew Cab Standard Box 4WD | $58,090 |
| Denali Crew Cab Short Box 2WD | $59,385 |
| Denali Crew Cab Short Box 4WD | $62,885 |
| Denali Crew Cab Standard Box 2WD | $59,685 |
| Denali Crew Cab Standard Box 4WD | $63,185 |
- Prices include destination and delivery charge of $1,595
Platform
- The 2021 Sierra Diesel 1500 rides on the GM T1 platform shared most directly with the 2021 Chevrolet Silverado 1500. The same basic architecture is also used on the 2021 Chevrolet Tahoe/2021 Chevrolet Suburban, 2021 GMC Yukon, and 2021 Cadillac Escalade.
- The 2021 Sierra Diesel Heavy Duty rides on a more capable version of the same GM T1 platform
Production
The 2021 Sierra Diesel was assembled at the following factories:
- GM Flint Assembly in Flint, Michigan, USA (HD)
- GM Fort Wayne Assembly in Fort Wayne, Indiana, USA (LD)
- GM Silao Assembly in Silao, Mexico (LD)
Availability
Production of the 2021 model year kicked off on September 14th for double cab and crew cab models, and September 21st for regular cab models. As such, we expect 2021 Sierra Diesel models to become available during the final quarter of 2020.
Beyond 2021
We expect the following future for the Sierra and Sierra Diesel beyond the 2021 model year:
- The light-duty Sierra 1500, now in its fourth generation as of the 2019 model year, should remain in production thru the 2025 model year
- The heavy-duty Sierra 2500HD and 3500HD, in their fourth generation as of the 2020 model year, should remain in production thru the 2026 model year
An all-new, next GMC Sierra will launch after the aforementioned models reach the end of their respective lifecycles.
Discussion
Discuss the 2021 GMC Sierra Diesel in our GMC forum.
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