Speedometer jumping question

Aris When you lubricate the lower 2/3 rd it takes some lube all the way to the bottom, leaving some the entire length . You don't want too much lube at the top end which may get into the speedo head. Worth a try.

Thanks guys!
George you might be so right, I have not lubricated the lower part of the outer cable, just the cable when inserting it from the top which has been done many times so far, so I will certainly try this. How did you lubricate the lower end? Maybe with a lubricated cable length from that end?
Mike I have tried with a short cable and a hand drill the speedometer that seems to work okay so as you say, I'm afraid the outer cable is the culprit, in which case the big problem is routing it in place, especially where it enters the floor of the cabin where my excellent carpet and the firewall carton have to be removed....

I had this same problem with a 1935 Auburn. After replacing the inner cable, sending the speedo to a shop several times with the same results, I finally replaced the outer cable housing and it stopped. There was a problem in the housing that couldn't be seen.
CORDially Mike

Aris ; Did you lubricate the new cable with special grease ? It is applied to the lower 2/3 of the cable.

Here I am again!
My speedometer needle is jumping wildly between between 20 to 40mph, but runs  steady before and after that range. The insert with the gear on it at the tranny end is ok, so I replaced the inner cable but with no success. I wonder if the problem is within the speedometer itself and I plan to open it up as I did decades ago when I repainted the etched numbers on the flat class plate. I read some speedometers have a built-in lubricating hole with felt fabric for oiling the shaft. I wonder if our speedometers have this option, otherwise I'll have to completely take it apart.