Speedometer Blues


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Feb 24, 2021
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Good Afternoon All
Not sure where to post this. Driveline issues seemed appropriate.
With the Part Barge ('65 Newport) in dry dock for the winter, I am addressing some 'gremlins' that pop up from time to time.
One of them is the speedometer. Every now and then (no reason that I can find) the speedometer needle will just start slamming from side to side. It will stop after a couple of miles and may not do it again for weeks. This does happen on the first start of the day.
Anyway the following is what has been looked at so far:
* Speedometer Cables (both) new and lubed. Car has add-on cruise control. Cables are not kinked or in tight radius.
* Cruise Control servo, rebuilt.
* Speedo drive pinion, no broken/chipped teeth
This brings me to the speedometer itself. I removed it today for a look-see. When I opened it up there was a black grease like substance smeared over the rotating assembly. I have had a few speedometers opened in the past and do not recall seeing grease. I do not know if someone has been in there before me.
Anyway is this normal? Should it be cleaned and re-greased? How do you clean it? (I do not want to disassemble the drive mechanism) .
Attached are a few pics .
Thanks to all who respond.
The "black grease" might be from somebody seeking to lube the mechanism with powdered graphite. If so, it will be hard to get off of your fingers.

Might check the cruise unit for easy turning when cold, as that's when it seems to happen.

For diagnostics, you can remove the cable itself from the casing and look for small burrs on the cable itself. Burrs which might mean some contact with the reinforcing mesh of the cable housing is happening. The cable should also have some cable lube on it, too, I suspect. If not, some approved lube might be in order, just a thin coating.

Just some thoughts,
I don't know what it is, but its not supposed to be there. I'm guessing your bouncing needle is some of that goop getting caught between the magnet assembly and the speedcup and grabbing the speedcup.

This is what mine looks like. The magnet shaft spins fast and is lubricated by the oil wick as shown. The speedcup & needle don't move enough to need any real lubrication. There maybe should be a tiny amount of grease on the plastic gears for the odometer shaft, but I'm not sure you need any there, definitely not globs like you found.
65 chrysler speedometer.jpg
While you are in this far, this would be a good time to make sure the odometer drums are working smoothly. Does your speedometer needle twitch when either of the odometers roll over to zero? If not, you're probably ok, but if it does, one of them is sticking a little. If it gets worse, and it locks up, it will chew up one of those plastic gears on the shafts.