its on the passanger side of the transmission, to the rear of the gear selector cable. its the black sensor with a wire plugged into it and only one bolt holding it in place. when the bolt is removed it just slips out, clean the filings off and reinstall it. put a little grease on the O-ring when you reinstall it.... this will save some check engine codes and makes for a good clean signal to the ECM. i started doing this and i have never got the speed sensor fault code as i use too(alot) as others have with the ranger. this sensor counts the teeth on the pinion gear and sends to ecm for speed and AWD input. if there is alot of trash on the sensor it will send in some cases corrupt information to the ecm inturn bad info and set off the light. it has worked for me but just wanted to share it with ya.