2006-07 GM w/ 8.1L Gas Engine 4wd 6-Speed LCT1000 Stage 4 Automatic Transmission PackageIncludes: ATS Extreme LCT1000 6-Speed Transmission w/ Numerous Proprietary Components and Modifications ATS TripleLok Torque Converter ATS Extra Deep Transmission Pan ATS CoPilot Electronic Transmission Controller ATS Billet Flex Plate Ability to hold 1000 and up horsepower. Features: 2006-07 2500/3500 GM Light Duty 8.1L Gas Engine 4wd 6-Speed LCT1000 Stage 4 Automatic Transmission Package