Remanufactured Duramax LLY 6.6L Engine For Sale
2004.5–2006 — 310 hp @ 3,000 RPM | 605 lb-ft @ 1,600 RPM
The Duramax LLY was the second generation, introduced mid-2004 as a 2004.5 model. It brought a significant torque increase to 605 lb-ft (up from 520) and added EGR for emissions compliance. The LLY mo...
Starting from $6,000 – $8,500 — 1-Year Unlimited Mileage Warranty
Duramax LLY Technical Specifications
About the Duramax LLY Engine
The Duramax LLY was the second generation, introduced mid-2004 as a 2004.5 model. It brought a significant torque increase to 605 lb-ft (up from 520) and added EGR for emissions compliance. The LLY moved the injectors from under the valve covers to a more accessible location, making future injector service much easier. Despite the addition of EGR, the LLY remains a pre-DPF engine, keeping the exhaust system relatively simple.
Duramax LLY Strengths
- Significant torque increase over LB7 (605 vs 520 lb-ft)
- Injectors relocated for much easier access and lower repair costs
- No DPF or DEF — still a relatively simple emissions setup
- Improved Allison 1000 transmission calibration
- Strong block and rotating assembly
- Good aftermarket support
Common Duramax LLY Issues (Addressed in Our Remanufactured Engines)
- Overheating under heavy load due to restricted airflow through the EGR cooler and intercooler
- EGR system can cause carbon buildup in the intake
- Head gasket failures can occur if overheating is not addressed
- Fuel injector return line leaks
Vehicles with the Duramax LLY
Duramax LLY Buying Guide
When purchasing a remanufactured LLY, ensure the EGR cooler has been inspected or replaced, as restricted EGR coolers are the primary cause of overheating. A quality remanufactured LLY should include updated head gaskets, a cleaned or new EGR cooler, and verified injectors. The LLY is identified by VIN code '2' in the 8th position.
Frequently Asked Questions — Duramax LLY
How much does a remanufactured Duramax LLY engine cost?
A remanufactured Duramax LLY 6.6L engine typically costs between $6,000 and $8,500. Pricing depends on the specific configuration and included components. All our LLY engines are rebuilt with updated EGR components and head gaskets. Call (631) 991-7700 for a quote.
Is the Duramax LLY reliable?
The Duramax LLY is a reliable engine when the overheating issue is addressed. The main concern is restricted EGR coolers causing elevated temperatures under heavy towing. With a properly maintained or updated EGR system, the LLY is a strong performer that regularly exceeds 300,000 miles.
What years is the Duramax LLY?
The Duramax LLY was installed in 2004.5 through 2006 Chevrolet Silverado 2500HD/3500 and GMC Sierra 2500HD/3500 trucks. It was also used in the 2006 Chevrolet Kodiak and GMC TopKick medium-duty trucks.
What is the difference between LB7 and LLY Duramax?
The LLY added EGR for emissions, increased torque from 520 to 605 lb-ft, and relocated the injectors for easier access. The LB7 has no EGR (simpler) but harder-to-access injectors. Both are pre-DPF engines without DEF requirements.
Duramax Troubleshooting Guides
Duramax Problems Guide
LB7 injectors, LBZ head gaskets, LML DEF issues — all generations covered.
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Step-by-step guide for installing your remanufactured engine.
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