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The 2004.5–2005 LLY Duramax refined GM’s diesel platform with improved cooling and stronger internal components, offering smoother towing and more dependable performance. Found in Silverado and Sierra HD trucks, the LLY is loved for its torque, throttle response, and tuning potential. Thoroughbred Diesel provides everything from intake and exhaust upgrades to maintenance kits and performance parts to keep your LLY running like new.
Our catalog of 2004.5–2005 LLY Duramax parts includes everything from routine maintenance items to high-performance upgrades. Popular options include AFE and Banks cold air intakes, Edge Juice with Attitude tuners for custom monitoring, and ARP head studs for reliability under heavy load. Many LLY owners also upgrade to FASS and AirDog lift pumps, BD Diesel turbo components, PPE transmission coolers, and MBRP exhaust systems to maximize power and towing performance. For maintenance, we carry OEM-quality filters, gasket kits, injectors, and sensors to keep your Duramax dependable mile after mile.
Whether you rely on your Silverado 2500HD for work or tow with your Sierra 3500HD on the weekends, Thoroughbred Diesel has the brands, parts, and experience to keep your LLY performing its best. Browse by department, explore trusted brands, or shop our featured products below — everything you need for your 2004.5–2005 LLY Duramax is right here.
The **2004.5–2005 LLY Duramax** brought improved power and drivability over the early LB7 models with updated injectors and tuning. These Thoroughbred Diesel videos dive into cooling upgrades, fuel system performance, and tuning tips to keep your LLY running cool, clean, and powerful.