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What's an RPO? Crucial Duramax Information!

Posted by Ben Lawson on Jul 18, 2022 6:00:00 AM



What's an RPO? Crucial Duramax Information!


This article will help you understand what an RPO is, how to find yours and when it will be needed.  An RPO or Regular Production Option is a GM-specific code, made up of 3 characters, that helps the manufacturer specify what configuration of options has been or needs to be applied to a vehicle. This can include anything from paint color to powertrain options. For Chevy/GMC Duramax trucks each type of engine can be signified by a different RPO code.

QR code


So, why is it important to know the RPO code for your engine?  Simply put, knowing your RPO code is like knowing the name of your specific Duramax engine. This can come in handy when troubleshooting your engine or when deciding to upgrade. Since each stock turbocharger can also be identified by the RPO Code, knowing the correct RPO will help you when buying an upgraded or replacement turbo.  This is also something you will want to know if you are buying a tune for your Duramax.  Each RPO code also has a different level of emissions equipment applied to the truck. Which may be an important factor in which one to choose.  




How do you find the RPO code for your specific vehicle you might wonder? Most RPO codes associated with GM products can be found by scanning the QR code on the vehicle's door sill. However, if you have an older model there’s an easy way of finding what you need. By identifying the 8th alphanumeric character in the VIN of the vehicle we can determine the RPO code. Here is a chart to help you decode your VIN. 


VIN Decode Chart



  • 2001-2004
  • Chevy Silverado HD, Chevy Kodiak, GMC Sierra HD, GMC TopKick
  • VIN Code “1”



  • 2004.5 - 2005
  • Chevy Silverado HD, GMC Sierra HD, (2006) Hummer H1
  • VIN Code “2”



  • 2006 - 2007 
  • Chevy Silverado HD, Chevy Kodiak, Chevy Express, GMC Sierra HD, GMC Savanah, GMC TopKick 
  • VIN Code “2” or “D” (if it is a model year 2006, your engine is an LBZ regardless of VIN Code)



  • 2007.5- 2010 
  • Chevy Silverado, Chevy Kodiak, GMC Sierra, GMC TopKick 
  • VIN Code “6”


  • 2010 - 2011 
  • Chevy Silverado, Chevy Express, GMC Sierra, GMC Savanah 
  • VIN Code “L”



  • 2011 - 2016
  • Chevy Silverado HD, GMC Sierra HD, 
  • VIN Code “8”



  • 2016 - Current 
  • Chevy Colorado, Chevy Express, GMC Savanah, GMC Canyon
  • VIN Code “1” (2016 and newer)



  • 2017 - Current 
  • Chevy Silverado HD, GMC Sierra HD
  • VIN Code “Y”


  • 2019-2021
  • Medium Duty Chevy and GMC Trucks
  • VIN Code “M”



So you have successfully identified your motor’s RPO, now what?

Now you have the ability to take your Duramax to the next level! By knowing what specific engine you have you can identify the parts and upgrades that will be an exact fit. Check out our website at www.duramaxtuner.com for our full list of upgrades for your specific RPO! 

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Topics: LLY, Duramax, Duramax Power, LML, LBZ, LB7, LMM, L5P, L5D, LWN, RPO