If the speedometer on your Mitsubishi Montero ever suddenly stops working, that likely means it is time to change the speed sensor. The speed sensor measures the shifting speed of your transmission's gears. If it stops working, you will need to replace it. The speed sensor on your Montero is located on the transmission. You should be able to replace the speed sensor in about 10 minutes using a few simple tools.
Park the Montero on level ground and set the emergency brake. Jack up the rear end of your Mitsubishi Montero.
Place the jack stands underneath the rear frame of the Montero. Lower the vehicle down onto the jack stands.
Locate the speed sensor on your Montero. It is mounted on the right side of the transmission housing.
Depress the release tab of the speed sensor's wiring harness. The release tab is mounted on the top of the sensor. As you depress the tab, pull the wiring harness plug out from the speed sensor.
Turn the nut at the base of the speed sensor counterclockwise with the socket set. Continue to turn the nut until the sensor comes free.
Install the new speed sensor by twisting it in clockwise. Tighten it with the socket set. Plug the wiring harness into the new sensor.
Jack the Montero up approximately eight inches. Remove the jack stands and lower the vehicle to the ground.