The BD Diesel performance AutoLoc is a computer that commands the torque converter lock-up clutch to stay applied when an exhaust brake is engaged. The AutoLoc ensures that 100% of the retarding force is being transferred in 3rd and 4th gears, thus, transmission oil temperatures remain low because converter slippage no longer occurs in these gears. The lock-up clutch applies with accelerator pedal pressure and the AutoLoc captures this signal. After shifting into overdrive in Dodge trucks, apply apply heavy accelerator pedal pressure or quickly release the pedal and the lock-up clutch will engage.
Exhaust brakes cause high automatic transmission fluid temperatures due to the torque converter slippage and without an AutoLoc, only 10-80% of the retarding force is transferred through the unlocked fluid coupling of a torque converter. You can drive the truck with the AutoLoc engaged all the time.