How do you change the speed sensor in a 2000 Ford F-150?

There is more than one speed sensor. There is one in the top of the differential housing. If you have a 4R70W transmission, there is a speed sensor in the side of it, and if you have a 4R100 transmission there are two speed sensors in it. If you have 4 wheel ant-lock brakes, there is a speed sensor in each front wheel hub. So there could be as many as 5 speed sensors. Which speed sensor are we replacing?