I just purchased a Superlift Truspeed Speed Sensor and installed it on my 2004, 5. 9 diesel with auto trans. This thing doesn't work for crap. My speedometer only registers 40mph when I am crusing 65+, no matter how much I adjust the unit. Also, when slowing down the speedometer takes a second or so to register 0, when my rig is already stopped. Removed the Superlift speed controller and reconnected the original wires to my ABS controller, speedo is off a bit, but works great!
Going to have the dealer cal the speedo tomorrow.
Just a heads up to others to avoid this particular unit.
Called Superlift tech support 3 times trying to get this unit up and working, pretty much useless on knowledge of 2004 and newer diesel rigs.
Buyer beware!!!!!