Prevent excessive wear, and costly unwarranted repairs on your braking system for your 2003-2007 Ford Power Stroke 6.0L, with a BD Diesel 4.0″ Exhaust Brake. Using variable butterfly technology, the BD Diesel exhaust brake provides peak retarding power throughout the engine′s entire rpm range. Also with a constantly exercising butterfly, carbon and rust deposits are reduced dramatically, providing miles of maintenance free service. The exhaust brake is controlled by a lighted on / off toggle switch or an optional stick-mounted rocker switch for manual transmissions. Automatic-equipped trucks prior to 2006 should use BD′s programmable AutoLoc package (already supplied with automatic truck) to electronically control torque converter clutch engagement. The AutoLoc package effectively reduces converter slippage, resulting in peak retarding performance.