Based on data from 37 vehicles, 2,039 fuel-ups and 730,384 miles of driving, the 2020 GMC Sierra 3500 HD gets a combined Avg MPG of 13.26 with a 0.17 MPG margin of error.

Any Engine Type 6.6L V8 DIESEL (35) 6.6L V8 GAS (1) Any Body Style Crew Cab Pickup (4) Any Submodel Base (1) SLT (5) AT4 (5) Denali (26)

Below you can see a distribution of the fuel-ups with 45 outliers (2.16%) removed.

Following shows the average MPG of each of the 37 vehicles in the system.

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• 2020 Sierra

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Jan 2023 • 63 Fuel-ups

  Property of brfs

• 16.0 Avg MPG

• Denali 3500 HD

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2021 • 96 Fuel-ups

  Property of 2010RWCM

• 13.5 Avg MPG

• 2020 GMC 3500 HD

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2020 • 348 Fuel-ups

  Property of Gassy1976

• 14.6 Avg MPG

• Dee 3500 HD

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2020 • 256 Fuel-ups

  Property of deewhite

• 13.0 Avg MPG

• My Sierra 3500 HD

  2020 GMC Sierra 3500 HD SLT 6.6L V8 DIESEL Automatic 10 Speed
  Added Jul 2020 • 167 Fuel-ups

  Property of abartlett

• 15.2 Avg MPG

• Damon’s Sierra 3500 HD Denali

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Feb 2020 • 283 Fuel-ups

  Property of Demon2JZ

• 11.0 Avg MPG

• GMC PlanetKiller

  2020 GMC Sierra 3500 HD SLT 6.6L V8 DIESEL Automatic 10 Speed
  Added Dec 2022 • 37 Fuel-ups

  Property of KyleMac

• 14.2 Avg MPG

• My Sierra 3500 HD

  2020 GMC Sierra 3500 HD SLT 6.6L V8 DIESEL Automatic 10 Speed
  Added Dec 2020 • 122 Fuel-ups

  Property of ghurd

• 14.3 Avg MPG

• GMC Sierra 3500 HD

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Apr 2023 • 41 Fuel-ups

  Property of audiododd

• 13.6 Avg MPG

• Star Lord vol. 2

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Jun 2021 • 35 Fuel-ups

  Property of rpar86

• 10.8 Avg MPG

• My Sierra 3500 HD

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 6 Speed
  Added Mar 2024 • 5 Fuel-ups

  Property of mlgriffin

• 15.8 Avg MPG

• My Sierra 3500 HD

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Jul 2020 • 130 Fuel-ups

  Property of hotsauce8815

• 12.0 Avg MPG

• My Sierra 3500 HD

  2020 GMC Sierra 3500 HD Denali 6.6L V8 GAS Automatic 6 Speed
  Added Jul 2020 • 75 Fuel-ups

  Property of jdmich

• 11.0 Avg MPG

• 2020 Def

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Apr 2023 • 8 Fuel-ups

  Property of brfs

• 721.2 Avg MPG

• My Sierra 3500 HD

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Jan 2020 • 7 Fuel-ups

  Property of Alec55

• 14.0 Avg MPG

• GMC

  2020 GMC Sierra 3500 HD AT4 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Nov 2022 • 63 Fuel-ups

  Property of kitakidscomcastnet

• 15.2 Avg MPG

• My Sierra 3500 HD

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Jun 2020 • 152 Fuel-ups

  Property of fox454

• 15.1 Avg MPG

• My Denali

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed Crew Cab Pickup
  Added Mar 2020 • 109 Fuel-ups

  Property of cmayfield682

• 17.2 Avg MPG

• My Sierra 3500 HD

  2020 GMC Sierra 3500 HD SLT 6.6L V8 DIESEL Automatic 10 Speed
  Added Mar 2020 • 41 Fuel-ups

  Property of freedom2020

• 8.2 Avg MPG

• My Sierra 3500 HD #1

  2020 GMC Sierra 3500 HD Denali 6.6L V8 DIESEL Automatic 10 Speed
  Added Nov 2022 • 3 Fuel-ups

  Property of Blueyfella

• 5.7 Avg MPG

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