Just FYI. The rear axle has an additional tone ring added the the ring gear that the hall effect sensor reads to produce the signal that is either sent to the ABS controller (4 wheel ABS) or the RWAL module which is the cheap ABS for the rear axle only (standard system on the trucks). You cant add this tone ring to an 8 3/4 or other axle as you need the hole in the pig and the ring on the gear. Thats why they have the conversion box to create a signal off the transmission. Vehicles equipped with the RWAL system also have one tone ring added to the left front wheel for a redundent speed sensor input, required on Electronic throttle applications. As stated earlier in this thread, you need the speed signal coming into the PCM for cruise control to work and really for good idle speed control etc.,