Currently, exhaust brake usage can cause high temperatures in the automatic transmission due to torque converter slippage, and, only 10% to 80% of the retarding force is transferred through the fluid coupling of most torque converters. The BD Torq/UnLoc commands the lock-up clutch of the torque converter to stay engaged when the BD Exhaust Brake is activated. This allows for up to 100% of the retarding force to be transferred in 3rd and 4th gear and the transmission oil temperature to remain low because of little to no slippage occurring when the converter is in these selected gears. The BD Torq/UnLoc is also able to prevent the ECM from activating the lock-up clutch when such an action would drag the engine rpm out of the optimum torque range, or, when traveling at such speeds that would cause the ECM to cycle the lock-up clutch in and out.
