I recently installed a jacobs exhaust brake that I purchased from the dodge dealership. I am confident that I installed it correctly, everything works as the manual has stated it will. But I noticed when the cruise control is set at 35 mph turning the exhaust brake on has the same effect as selecting tow/haul mode on the transmission. The engine jumps from 1100 rpm to 1500 rpm. Is this normal? My truck is a 3500 single wheel mega cab cummins with auto trans. Also what is the cpl number?