Speed Sensor Problem

I have a '00 F150 V6 5spd. My speedomoter/odometer were dropping out intermittently so I changed the speed sensor (located in the rear end). The speedometer/odometer still drops out intermittently, so what else could be the problem??

Hey 9ball, according to my parts catalog, this truck calls for a SC147 sensor(Standard ignition). The picture of this sensor shows it to be a transmission mounted sensor. Ford has used both trans mounted and diff mounted units. I thought by 97 they had switched to all diff mounted and done away with the trans mounted unit, but not according to my books. Look on the trans, on the extension housing where the speedometer cable would go if it had one. If theres a device in that hole with a harness attached, thats it, if not it will have a blank plate over the hole and its in the diff.

Great, thanks a bunch! I'll be able to get it up on a lift in the next day or two so I'll check it out!