If you own a GM truck or van with a Duramax diesel, knowing which engine you have is essential for maintenance, upgrades, and performance tuning. The fastest way to identify your Duramax engine is by checking the 8th digit of your VIN—this single character reveals your engine’s generation, and each has its own specs and quirks. Here’s a breakdown for all major Duramax engines, including model years, horsepower, and torque figures.
| 8th VIN Digit | Engine Code | Model Years | Horsepower | Torque |
|---|---|---|---|---|
| 1 | LB7 | 2001–2004 | 300 hp @ 3,100 rpm | 520 lb-ft @ 1,800 rpm |
| 2 | LLY | 2004.5–2006 | 310 hp @ 3,000 rpm (auto) | 605 lb-ft @ 1,600 rpm |
| D | LBZ | 2006–2007 | 360 hp @ 3,200 rpm | 650 lb-ft @ 1,600 rpm |
| 6 | LMM | 2007.5–2010 | 365 hp @ 3,200 rpm | 660 lb-ft @ 1,600 rpm |
| 8 | LML | 2011–2016 | 397 hp @ 3,000 rpm | 765 lb-ft @ 1,600 rpm |
| L | LGH | 2011–2016* | 335 hp @ 3,100 rpm | 685 lb-ft @ 1,600 rpm |
| Y | L5P | 2017–2024+ | 445–470 hp @ 2,800 rpm | 910–975 lb-ft @ 1,600 rpm |
*LGH was used in vans and chassis cab trucks, not pickups.
for Silverado/Sierra HD and medium-duty trucks.
Known for strong performance and reliability, but prone to injector issues.
.
Introduced variable-geometry turbo and EGR for emissions.
Slight bump in power, especially with automatic transmissions.
; 300 hp, 520 lb-ft (manual).
Highly sought after for performance and reliability.
Stronger internals, no DEF system, and robust tuning potential.
.
Added diesel particulate filter (DPF) for emissions.
Slight power increase, similar reliability to LBZ.
.
Major redesign with increased power and torque.
Introduced DEF (diesel exhaust fluid) and advanced emissions controls.
.
Variant of LML for vans and chassis cabs.
Lower output for commercial durability.
(trucks); 260 hp, 525 lb-ft (vans).
All-new design, the most powerful Duramax to date.
2024+ models boast even higher output.
(2017–2023); 470 hp, 975 lb-ft (2024+).
: Many components (injectors, turbos, electronics) differ between generations.
: Tuning, fueling, and turbo options are engine-specific.
: Common issues and service intervals vary by engine code.
Look at the driver’s side dashboard (visible through the windshield) or on your registration/title. The 8th character is your Duramax engine code.
At NorCal Diesel Performance, we’re experts in all generations of Duramax engines. Whether you’re chasing more power or just want to keep your truck running strong, knowing your VIN is the first step—contact us with your VIN and let’s get started!
A. You can find your vehicle identification number (VIN) on the driver's side dashboard, visible through the windshield, or on your registration and title documents. The 8th character of the VIN reveals which Duramax engine generation your truck or van is equipped with.
A. Identifying your Duramax engine is essential for ordering the correct replacement parts, choosing compatible performance upgrades, and following the proper maintenance schedule. Components such as injectors, turbos, sensors, and tuning options can vary significantly between engine generations.
A. The L5P Duramax, found in 2017-present GM HD trucks, is the most powerful Duramax engine produced to date. Current 2024+ models are rated at up to 470 horsepower and 975 lb-ft of torque, making them the highest-output factory Duramax engines available.
A. Many diesel enthusiasts consider the 2006-2007 LBZ Duramax one of the most desirable platforms for performance modifications. It features strong internal components, excellent reliability, and does not utilize a DEF system, making it popular among truck owners seeking increased horsepower and towing performance.
A. Not always. While some components may be compatible, many critical parts, including fuel injectors, turbochargers, emissions equipment, and electronics, are specific to certain Duramax engine generations. Verifying your engine code before purchasing parts can help prevent costly compatibility issues.
