BD Diesel Allison Lock-up & Pressure Controller - 2011-2015.5 Chevy Duramax 6.6LThe Allison transmission control strategy works very well, even allowing torque converter clutch lockup in second gear in some cases. However, in high horsepower applications lockup is sometimes inhibited due to increased torque converter stall speed. Because of this, auxiliary lockup control devices are required to reliably engage the clutch for racing or high performance applications. The BD Allison Lockup Controller gives you control over your