The New 24 Pin ATS Co-Pilot for 2001-05 GM, 5 speed Allison 1000 and 6.6L Duramax, Controls Transmission Pressure and TCC lock up based on Boost Pressure(MAP), Vehicle Speed(VSS) and Throttle Position(TPS)Features: 2001-2005 2500/3500 Duramax GM Light Duty 6.6L 5 speed Allison 1000