2004.5-2005 GM Duramax 6.6L LLY Complete Transmissions

The factory transmission equipped on your 2004.5-2005 GM 6.6L Duramax LLY build becomes a weak point after you add increased levels of horsepower and torque to the engine. Instead of trying to piece together the best transmission upgrades for your particular setup, choose from our selection of complete transmissions for reliable and consistent performance under every circumstance. These complete transmissions for your GM 2500/3500 drop right into place of your Sierra/Silverado's stock components and will handle the huge levels of power your truck is throwing down. 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.