Duramax VIN Decoder
Decode your VIN free to confirm a Duramax diesel and its generation. From NHTSA data, no signup.
Modern road VIN: 17 characters, no I / O / Q. Find your VIN.
Try an example:
Examples demonstrate the public data source; they are not vehicles offered for sale. Missing fields mean not reported, not “none.”
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Specifications reported by NHTSA. Empty data does not mean the feature is absent. Compare configuration labels and manufacturer records before buying parts.
About the Duramax
Built by
General Motors — Chevrolet & GMC
Fuel: Diesel
Displacements
6.6L V8 turbodiesel · 3.0L inline-6 turbodiesel
Common in
Silverado 2500 HD, Silverado 3500 HD, Sierra 2500 HD, Sierra 3500 HD, Silverado 1500 (3.0)
Duramax is GM’s diesel line. The 6.6L V8 turbodiesel powers the Silverado and Sierra heavy-duty trucks (2500/3500), while the newer 3.0L inline-six turbodiesel is offered in the light-duty Silverado and Sierra 1500. Each generation carries its own RPO code (LB7, LLY, LBZ, LMM, LML, L5P for the 6.6; LM2/LZ0 for the 3.0).
The generation is not spelled out plainly in the VIN — the 8th character encodes the engine, but the specific code depends on model and year. Decode your VIN above to confirm it’s a diesel and read the engine details, then match the model year to the Duramax generation.
OPTIONAL CHECKING TOOLS
Tools for reading a hidden marking
For a VIN plate, engine stamping or equipment label you cannot see clearly, a small light or mirror may help.
Telescoping LED inspection mirror
An adjustable lighted mirror for viewing a serial plate or engine marking at an awkward angle.
Inspect only with the vehicle or machine safely parked, switched off and cool.
View on AmazonLE LED pen flashlights
Two pocket lights with clips for reading VIN plates, equipment labels and engine markings.
Each light uses two AAA batteries (not included).
View on AmazonAs an Amazon Associate I earn from qualifying purchases. Check price and fit on Amazon.
How your VIN shows the Duramax
On most vehicles the 8th character of the VIN encodes the engine — but the specific letter or number that means a given engine is make-, model- and year-specific, so there is no universal code to look up. The dependable method is to decode the whole VIN and read the engine and fuel fields, which is exactly what the free tool at the top of this page does. See how VINs encode the engine for the full explanation.
Remember the VIN reflects the factory-installed engine — a later engine swap is not recorded in the VIN.
Makes that use the Duramax
Duramax VIN — FAQ
Which Duramax generation do I have?
Decode the VIN to confirm the 6.6L (or 3.0L) diesel, then use the model year: the 6.6 runs LB7 (2001–04), LLY, LBZ, LMM, LML, and L5P (2017+). The VIN’s engine field plus the year points to the generation.
How do I know if my Silverado is a Duramax?
Decode the VIN and read the fuel type and engine fields — a Duramax returns a diesel 6.6L V8 (HD trucks) or 3.0L inline-6 (1500). Gas trucks will show a gasoline V6 or V8 instead.
Other engine families
See also the VIN year chart or decode any VIN.