2004.5-2005 GM 2500HD/3500HD 6.6L LLY Duramax Transmission Upgrades

If you've added high-performance modifications to your 2004.5-2005 GM 6.6L Duramax, your transmission and transfer case will likely experience the effects of increased horsepower and torque throughout your truck's drivetrain. Our premium transmission upgrades for your GM 2500HD/3500HD ensure that your transmission remains stable as you boost power for enhanced drivability and towing capabilities. At Alligator Performance, we provide a variety of transmission upgrades, including transmission pans, torque converters, flex plates, modules, and complete transmissions, all designed to deliver reliable performance for your 6.6L Duramax! Pair your transmission upgrades with our full array of  Engine Upgrades!  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.