2004.5-2005 GM Duramax 6.6L LLY Chips, Modules & Tuners

The powerful 6.6L Duramax LLY under the hood of your 2004.5-2005 GM Sierra/Silverado may throw down a huge amount of horsepower and torque off the factory line, but there's plenty more power and performance hidden away and waiting to be unleashed. These premium performance tuners help unlock more horsepower, torque, and throttle response by making adjustments within your truck's ECM. Additionally, these tuners can make your GM 2500/3500 feel like a whole new rig by correcting your rig for an increase in tire size, change in gear ratio, or a brand new exhaust system that requires tuning. Many of these devices even work overtime as effective vehicle monitors so you can better keep tabs on your truck's critical running information to spot problems before they become disasters. Keep tabs on your engine parameters and experience a more powerful ride with any of the high-quality tuners we offer for the GM 6.6L Duramax LLY. GM Duramax Fitments: 2004, 2005 GM 6.6L Duramax. Submodel Fitments: WT, Custom, LT, LTZ, High Country, 1LT, 2LT, Pro, SLE, SLT, AT4, Denali. Some exceptions apply, please see individual product pages for specific fitments.