Wanted to ask if anyone has had this issue and solved it. When driving my 91 Cherokee (automatic), the speedometer will at times swing to 0 then make several attempts to get back to the correct speed then drop back to 0. After a few days of this it now mostly stays on 0. My tachometer is fine. I am going to test my cruise control servo tomorrow and I did pick up a used cluster gear at the wrecking yard in case I end up replacing the speedometer gauge. Any thoughts out there? Am I on the correct diagnostic trail?

 

Check the bolt holding the speed sensor. If thats not it, remove the speed sensor and see if the cable spins. Should show up on the cluster, i think. If thats not it, check the gear on the output shaft as it may have fallen apart. Like this one. Not mine.

 

Where is the gear on the output shaft located?

 

Pull the speed sensor (the speedo gear should come out with it, i believe) and shine a flashlight into the hole. You should be able to see the speedo drive gear on the output shaft. Your gears may not be the same colors as pictured as it varies with gear ratio. You might leak a couple drops of fluid so dont freak if it takes a leak on you. Dont forget the safety goggles when working under a vehicle.

 

4x4?