BD Diesel Allison Pressure Controller - 2011-2016 Chevy Duramax 6.6LAllison transmissions utilize variable line pressure that adjusts to different engine load to improve fuel economy. The problem with this is that it drops line pressure after a shift, causing clutch slippage and failure in higher powered trucks. The BD pressure controller module boosts line pressure up to 275psi when the engine is over 15psi boost and runs stock pressure under normal conditions prevent harsh shifting. The kit is fully plug and play.