Not lubricated
It's usually the cable or the speedometer head in the dash that have problems Is it possible to lubricate the where the cable and the speedometer head cluster meet? If so, how do you get into the head or cluster?
High pitched noise from a Toyota 4 Runner can be due to loose bearing. To check on this, touch each rim. One bearing will noticeably be hotter than the others.
Yes, if it has a mechanical speedometer. It can also be a relay that is clicking.
The cable needs lubricating. Remove the speedometer cable and lubricating it with special lube for that purpose. Any auto parts store can provide the proper lube. Remove the cable and clean it throughly with spray brake cleaner. Let it dry and apply the lube. Reinstall the cable and you should see the needle stop jumping and making noise.
I believe the head is the part of the speedometer that is directly behind the faceplate of the gauge. It takes the input from the cable spinning at X rpm's (or sensor if electronic) and converts it mechanically into what your speedometer gauge indicates on the faceplate.
You could disconnect the cable down at the transmission, drive it around, and see if the noise has quit. Some cars don't have a cable-the speedo is electronic, so then you might have a vacuum leak somewhere under the dash.
Fixing it depends on what the speedometer is doing. Chances are its making a funny noise and the needle is bouncing around. This would be due to a damaged or unlubricated speedometer cable. It is a cable that spins around in a plastic sheath connected to the back or your speedometer and to your transmission. Often times removing it and filling it with graphite powder will solve the problem. If its severely damaged you can replace it with a new one. If the cable isn't the problem you may have to replace the speedometer itself.
Trouble? Noise maybe or a wild speedo gage? Unscrew the cable at the dash side (from under the hood) and spray some WD40 inside the cable. Try that or replace the cable.
The speedometer cable is either worn out or loose.
cable could be loose or faulty speedo..
There could be many causes, but IF your vehicle uses a mechanical speedometer cable then if the lubrication [grease] has dried out then the "sticking" of the rotating inner cable against the outer protective cable could be causing the tick.
If the grinding sound seems to be coming from the speedometer and grinds faster as your speed increases, the likely cause is the speedometer cable. At least some 1990 Dodge trucks (mine) have electric speedometers Len