Remanufactured Duramax LB7 6.6L Engine For Sale
2001–2004 — 300 hp @ 3,100 RPM | 520 lb-ft @ 1,800 RPM
The Duramax LB7 was the first generation of the Duramax 6.6L diesel engine, developed jointly by General Motors and Isuzu. Debuting in the 2001 Chevrolet Silverado HD and GMC Sierra HD, the LB7 replac...
Starting from $6,000 – $8,500 — 1-Year Unlimited Mileage Warranty
Duramax LB7 Technical Specifications
About the Duramax LB7 Engine
The Duramax LB7 was the first generation of the Duramax 6.6L diesel engine, developed jointly by General Motors and Isuzu. Debuting in the 2001 Chevrolet Silverado HD and GMC Sierra HD, the LB7 replaced the aging 6.5L Detroit Diesel and immediately established GM as a serious contender in the diesel pickup truck market. The LB7 introduced Bosch common rail fuel injection to the light-duty diesel segment, delivering 300 horsepower and 520 lb-ft of torque — numbers that were class-leading at the time. Paired exclusively with the Allison 1000 5-speed automatic transmission, the LB7 Duramax offered a smooth, powerful towing experience that rivaled the Cummins 5.9L and Ford 7.3L Power Stroke.
Duramax LB7 Strengths
- No EGR system — runs cleaner internally with less carbon buildup
- No DPF or DEF — simpler exhaust system with lower maintenance costs
- Bosch common rail injection was revolutionary for its time
- Allison 1000 transmission pairing is extremely durable
- Strong aftermarket support for performance upgrades
- Proven reliability with many engines exceeding 300,000 miles
Common Duramax LB7 Issues (Addressed in Our Remanufactured Engines)
- Injector failure is the most common issue — replacement requires removing the valve covers and intake manifold
- Injector harness chafing can cause misfires and rough running
- Water pump failure is common at higher mileage
- Fuel filter housing can develop leaks
Vehicles with the Duramax LB7
Available Duramax LB7 Remanufactured Engines
Duramax LB7 Buying Guide
When purchasing a remanufactured Duramax LB7, verify that the injectors have been replaced with updated Bosch units. The LB7's injectors are the most expensive to replace of any Duramax generation because they are located under the valve covers. A quality remanufactured LB7 should include new or remanufactured injectors, a new water pump, and updated injector harnesses. The LB7 is identified by the VIN code '1' in the 8th position.
Frequently Asked Questions — Duramax LB7
How much does a remanufactured Duramax LB7 engine cost?
A remanufactured Duramax LB7 6.6L engine typically costs between $6,000 and $8,500 depending on the configuration and whether new injectors are included. At US Engine Production, all our LB7 engines come with updated Bosch injectors and a comprehensive warranty. Call (631) 991-7700 for an exact quote.
Is the Duramax LB7 a good engine?
Yes, the Duramax LB7 is an excellent engine. It was the first Duramax generation and is valued for its simplicity — no EGR, no DPF, and no DEF system. With proper maintenance and quality injectors, the LB7 regularly exceeds 300,000 miles. Its pre-emissions design makes it popular with both work truck owners and performance enthusiasts.
What are common Duramax LB7 problems?
The most common LB7 issue is injector failure, which can cause rough running, white smoke, and fuel dilution in the oil. The injectors are located under the valve covers, making replacement more labor-intensive than later generations. Other common issues include injector harness chafing, water pump failure, and fuel filter housing leaks. Our remanufactured LB7 engines address all these known issues with updated components.
What year trucks have the Duramax LB7?
The Duramax LB7 was installed in 2001-2004 Chevrolet Silverado 2500HD/3500 and GMC Sierra 2500HD/3500 trucks. Some early 2004.5 models transitioned to the LLY. You can identify an LB7 by the VIN code '1' in the 8th position.
How many miles can a Duramax LB7 last?
A well-maintained Duramax LB7 can last 300,000 to 500,000+ miles. The key to longevity is regular oil changes, clean fuel, and addressing injector issues promptly. Many LB7 trucks used for towing and commercial work have exceeded 400,000 miles on the original engine block.
Can you put a Duramax LB7 in a newer truck?
While technically possible, swapping an LB7 into a newer truck is complex due to different wiring harnesses, ECM programming, and transmission compatibility. The LB7 pairs with the Allison 1000 5-speed, while newer trucks use 6-speed or 10-speed transmissions. It's generally more practical to install the correct generation Duramax for your truck's model year.
Duramax Troubleshooting Guides
Duramax Problems Guide
LB7 injectors, LBZ head gaskets, LML DEF issues — all generations covered.
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Complete pricing for remanufactured Duramax engines by generation.
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Read Guide →Installation Guide
Step-by-step guide for installing your remanufactured engine.
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