Sierra 2WD — Diesel · RWD · 3L 6-cyl · 26 MPG
Official vehicle configuration guide
2021 GMC Sierra
Compare 36 EPA-tested configurations, including the exact powertrain, fuel, driven wheels, engine, transmission and efficiency data available for this model year.
U.S. market 36 EPA configurations GasolineFlex fuelDiesel
Compare researched years → Official EPA configuration data
36 configurationsChoose the closest tested configuration.
These entries distinguish powertrains and driveline combinations recorded by the U.S. EPA. They help narrow the vehicle, but they are not guaranteed retail trim or option-package names.
Match the fuel type, drive and transmission shown on the vehicle documents. A dealer package may use a different name.
Selected configurationSierra 2WD — Gasoline · RWD · 5.3L 8-cyl · 17 MPG · Automatic 6-spd
Gasoline- Fuel
- Regular
- Engine
- SIDI; Active Fuel Management
- Drive
- RWD
- Transmission
- Automatic 6-spd
- EPA combined
- 17 MPG combined
- City / highway
- 15 / 21 MPG
- Electric motor
- Not listed
- Range
- Not listed
- 240 V charge time
- Not listed
- Secondary / blended economy
- Not listed
- EPA vehicle class
- Standard Pickup Trucks 2WD
- Stop-start system
- No
Sierra 2WD — Gasoline · RWD · 5.3L 8-cyl · 17 MPG · Automatic 6-spd selected.
Configuration is not the same as trim. EPA records can separate engines, fuel systems, transmissions or driven wheels without identifying badges such as LX, XLE or Touring. Confirm the retail trim with the window sticker, build sheet or manufacturer VIN portal.
Compare every tested configuration
36 official recordsMechanical and efficiency differences.
All rows are visible in the page and link to their exact government record. EPA configurations identify tested hardware, not guaranteed retail trim names.
Sierra 2WD — Flex fuel · RWD · 5.3L 8-cyl · 16 MPG
View all 36 EPA configuration rows
| EPA carline | Powertrain | Engine / motor | Drive | Transmission | Combined | Range / charge | Source |
|---|---|---|---|---|---|---|---|
| Sierra 2WD — Gasoline · RWD · 5.3L 8-cyl · 17 MPG · Automatic 6-spd | GasolineRegular | SIDI; Active Fuel Management | RWD | Automatic 6-spd | 17 MPG15 city / 21 highway | — | EPA record ↗ |
| Sierra 2WD — Flex fuel · RWD · 5.3L 8-cyl · 16 MPG | Flex fuelGasoline or E85 | SIDI; FFV | RWD | Automatic 6-spd | 16 MPG15 city / 19 highway | 288 mi EV | EPA record ↗ |
| Sierra 2WD — Gasoline · RWD · 5.3L 8-cyl · 19 MPG | GasolineRegular | SIDI; with Cylinder Deactivation | RWD | Automatic 8-spd | 19 MPG17 city / 23 highway | — | EPA record ↗ |
| Sierra 2WD — Diesel · RWD · 3L 6-cyl · 26 MPG | DieselDiesel | 3 L · 6-cyl | RWD | Automatic 10-spd | 26 MPG23 city / 30 highway | — | EPA record ↗ |
| Sierra 2WD — Gasoline · RWD · 4.3L 6-cyl · 17 MPG | GasolineRegular | SIDI | RWD | Automatic 6-spd | 17 MPG16 city / 21 highway | — | EPA record ↗ |
| Sierra 2WD — Gasoline · RWD · 2.7L 4-cyl · 21 MPG · Automatic 8-spd · SIDI; 4-mode/Sport transmission | GasolineRegular | SIDI; 4-mode/Sport transmission | RWD | Automatic 8-spd | 21 MPG20 city / 23 highway | — | EPA record ↗ |
| Sierra 2WD — Gasoline · RWD · 2.7L 4-cyl · 21 MPG · Automatic 8-spd · SIDI; 3-mode transmission (work truck) | GasolineRegular | SIDI; 3-mode transmission (work truck) | RWD | Automatic 8-spd | 21 MPG20 city / 23 highway | — | EPA record ↗ |
| Sierra 2WD — Gasoline · RWD · 5.3L 8-cyl · 16 MPG | GasolineRegular | SIDI | RWD | Automatic 6-spd | 16 MPG14 city / 21 highway | — | EPA record ↗ |
| Sierra 2WD — Gasoline · RWD · 5.3L 8-cyl · 17 MPG · Automatic 8-spd | GasolineRegular | SIDI | RWD | Automatic 8-spd | 17 MPG15 city / 22 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 6.2L 8-cyl · 17 MPG | GasolinePremium | SIDI; Stop-Start | 4WD | Automatic 10-spd | 17 MPG16 city / 20 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 5.3L 8-cyl · 17 MPG | GasolineRegular | SIDI; Active Fuel Management | 4WD | Automatic 6-spd | 17 MPG15 city / 20 highway | — | EPA record ↗ |
| Sierra 4WD — Flex fuel · 4WD · 5.3L 8-cyl · 16 MPG | Flex fuelGasoline or E85 | SIDI; FFV | 4WD | Automatic 6-spd | 16 MPG14 city / 18 highway | 288 mi EV | EPA record ↗ |
| Sierra 4WD — Diesel · 4WD · 3L 6-cyl · 24 MPG | DieselDiesel | 3 L · 6-cyl | 4WD | Automatic 10-spd | 24 MPG22 city / 26 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 5.3L 8-cyl · 19 MPG | GasolineRegular | SIDI; Stop-Start | 4WD | Automatic 10-spd | 19 MPG16 city / 22 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 5.3L 8-cyl · 18 MPG · Automatic 8-spd | GasolineRegular | SIDI; with Cylinder Deactivation | 4WD | Automatic 8-spd | 18 MPG16 city / 21 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 4.3L 6-cyl · 17 MPG | GasolineRegular | SIDI | 4WD | Automatic 6-spd | 17 MPG15 city / 20 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 2.7L 4-cyl · 19 MPG · Automatic 8-spd · SIDI; 4-mode/Sport transmission | GasolineRegular | SIDI; 4-mode/Sport transmission | 4WD | Automatic 8-spd | 19 MPG18 city / 21 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 2.7L 4-cyl · 19 MPG · Automatic 8-spd · SIDI; 3-mode transmission (work truck) | GasolineRegular | SIDI; 3-mode transmission (work truck) | 4WD | Automatic 8-spd | 19 MPG18 city / 20 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 5.3L 8-cyl · 16 MPG · Automatic 6-spd | GasolineRegular | SIDI | 4WD | Automatic 6-spd | 16 MPG14 city / 20 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 5.3L 8-cyl · 16 MPG · Automatic 8-spd | GasolineRegular | SIDI | 4WD | Automatic 8-spd | 16 MPG14 city / 20 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 6.2L 8-cyl · 16 MPG | GasolinePremium | SIDI | 4WD | Automatic 10-spd | 16 MPG15 city / 20 highway | — | EPA record ↗ |
| Sierra 4WD — Gasoline · 4WD · 5.3L 8-cyl · 18 MPG · Automatic 10-spd | GasolineRegular | SIDI | 4WD | Automatic 10-spd | 18 MPG15 city / 21 highway | — | EPA record ↗ |
| Sierra 4WD AT4 — Gasoline · 4WD · 6.2L 8-cyl · 17 MPG | GasolinePremium | SIDI; Stop-Start | 4WD | Automatic 10-spd | 17 MPG15 city / 19 highway | — | EPA record ↗ |
| Sierra 4WD AT4 — Diesel · 4WD · 3L 6-cyl · 24 MPG | DieselDiesel | 3 L · 6-cyl | 4WD | Automatic 10-spd | 24 MPG22 city / 26 highway | — | EPA record ↗ |
| Sierra 4WD AT4 — Gasoline · 4WD · 5.3L 8-cyl · 18 MPG · Automatic 10-spd | GasolineRegular | SIDI | 4WD | Automatic 10-spd | 18 MPG16 city / 21 highway | — | EPA record ↗ |
| Sierra 4WD AT4 — Gasoline · 4WD · 5.3L 8-cyl · 18 MPG · Automatic 8-spd | GasolineRegular | SIDI; with Cylinder Deactivation | 4WD | Automatic 8-spd | 18 MPG16 city / 21 highway | — | EPA record ↗ |
| Sierra 4WD AT4 — Gasoline · 4WD · 5.3L 8-cyl · 16 MPG · Automatic 6-spd | GasolineRegular | SIDI | 4WD | Automatic 6-spd | 16 MPG14 city / 18 highway | — | EPA record ↗ |
| Sierra 4WD AT4 — Gasoline · 4WD · 5.3L 8-cyl · 16 MPG · Automatic 8-spd | GasolineRegular | SIDI | 4WD | Automatic 8-spd | 16 MPG14 city / 20 highway | — | EPA record ↗ |
| Sierra 4WD AT4 — Gasoline · 4WD · 6.2L 8-cyl · 16 MPG | GasolinePremium | SIDI | 4WD | Automatic 10-spd | 16 MPG14 city / 19 highway | — | EPA record ↗ |
| Sierra 4WD AT4 — Gasoline · 4WD · 5.3L 8-cyl · 17 MPG | GasolineRegular | SIDI | 4WD | Automatic 10-spd | 17 MPG15 city / 21 highway | — | EPA record ↗ |
| Sierra Cab Chassis 2WD — Gasoline · RWD · 5.3L 8-cyl · 15 MPG | GasolineRegular | SIDI | RWD | Automatic 6-spd | 15 MPG14 city / 18 highway | — | EPA record ↗ |
| Sierra Cab Chassis 2WD — Gasoline · RWD · 4.3L 6-cyl · 17 MPG | GasolineRegular | SIDI | RWD | Automatic 6-spd | 17 MPG15 city / 19 highway | — | EPA record ↗ |
| Sierra Cab Chassis 2WD — Gasoline · RWD · 5.3L 8-cyl · 14 MPG | GasolineRegular | SIDI | RWD | Automatic 6-spd | 14 MPG13 city / 18 highway | — | EPA record ↗ |
| Sierra Cab Chassis 4WD — Gasoline · 4WD · 5.3L 8-cyl · 15 MPG | GasolineRegular | SIDI | 4WD | Automatic 6-spd | 15 MPG14 city / 17 highway | — | EPA record ↗ |
| Sierra Cab Chassis 4WD — Gasoline · 4WD · 4.3L 6-cyl · 15 MPG | GasolineRegular | SIDI | 4WD | Automatic 6-spd | 15 MPG14 city / 16 highway | — | EPA record ↗ |
| Sierra Cab Chassis 4WD — Gasoline · 4WD · 5.3L 8-cyl · 14 MPG | GasolineRegular | SIDI | 4WD | Automatic 6-spd | 14 MPG13 city / 17 highway | — | EPA record ↗ |
At a glance
What the official records cover.
Each option above is tied to a unique FuelEconomy.gov vehicle ID. EPA names sometimes expose a retail badge such as LE or Woodland Edition, but many records identify only the tested mechanical configuration.
Sierra 2WD, Sierra 4WD, Sierra 4WD AT4, Sierra Cab Chassis 2WD, Sierra Cab Chassis 4WD
Gasoline, Flex fuel, Diesel
RWD, 4WD
5.3L 8-cyl, 3L 6-cyl, 4.3L 6-cyl, 2.7L 4-cyl, 6.2L 8-cyl
How to identify yours
Match the hardware before the badge.
- 1
Start with fuel and powertrain. Check whether the vehicle is gasoline, diesel, hybrid, plug-in hybrid, electric or fuel-cell.
- 2
Match driven wheels and engine. Use FWD, RWD, AWD or 4WD plus displacement/cylinder information from the window sticker or registration.
- 3
Confirm the exact EPA record. Select the closest option and open its FuelEconomy.gov link. Use a VIN-specific build sheet when you need the retail trim or option package.
Source: U.S. Department of Energy / EPA FuelEconomy.gov dataset ↗ · U.S. market snapshot 2026-11-04. Economy values are official estimates, not a promise of real-world consumption.
02 Feature research status
The configuration guide is live.
The official mechanical and efficiency data for this exact vehicle is published above. Hidden-feature instructions are a separate layer: they appear only after the correct owner manual, model-year scope and equipment caveats have been checked.
EPA configurations publishedOfficial records linkedOwner-manual features in review
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