Duramax VIN Decoder

Decode your VIN free to confirm a Duramax diesel and its generation. From NHTSA data, no signup.

17 characters, no I / O / Q. Where do I find my VIN?

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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.

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

ChevroletVIN decoder GMCVIN decoder

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

HEMIVIN guide LS / LTVIN guide VortecVIN guide Power StrokeVIN guide EcoBoostVIN guide Coyote 5.0VIN guide CumminsVIN guide Engine codeby VIN

See also the VIN year chart or decode any VIN.