The perfect complement to the Pacbrake on the 03 Automatic trucks is the Suncoast Torque Locker TLIN. For the 48 RE trucks, it keeps the converter locked in Drive while decelerating to the lowest possible speed. For mine, it was about 27 mph. Currently, you cannot downshift while the TC is locked during braking. If you want to downshift, you have to hit the throttle for a second, downshift, then continue braking. The electronics won't let the downshift occur while the TC is locked with the TLIN. My thanks go out to Joe at Suncoast!