It would probably be cheaper to replace the cable, check with your local auto wrecker. This used part should be very inexpensive, compared to repairing it.
If your speedometer is cable driven and not electronic, it sounds like the cable needs to be lubricated. You remove the cable from the back of the speedometer and pull out the inner cable and slide it back in while lubericating it with some speedo grease.
No, the speedometer is driven electrically from the PCM.
There are several things you can do to repair your speedometer. You can replace the speedometer cable. You can replace the speed sensor in the transmission.
There is no Cable it is a speed sensor on the transmission
Loose or failing speedometer cable Speedometer head needs repair
Most likely speedometer cable
The 2000 Mercury Sable starter will have three retaining bolts. There will be two cable retaining nuts on the front of the starter.
If the speedometer is not working it probably needs a new speedometer cable. If the speedometer is actually broken either take it to as speedometer repair shop or replace it.
Actually , it doesn't have a conventional speedometer cable , it has an electronic speedometer and a vehicle speed sensor ( VSS ) according to my Haynes repair manual
A 1995 Jeep Grand Cherokee does "NOT" have a speedometer cable. It has an electronic speedometer with a built in motherboard. It receives its signsls from sensors on the transmission and the transfer case.
A 1994 Plymouth Sundance/Duster does not use a speedometer cable. Instead, it uses a Speed Sensor located on the transmission.
To repair the speedometer on the 2003 Suburban, first check to see what is causing the malfunction. You might need to replace a fuse or even the cable.