Rather than just lubricating the lower end, pull the inner cable out and apply a light weight grease or some oil to it. Then push it back in.
The most difficult part of this is getting the square upper end to go back into the speedometer but if you keep turning the cable slightly and trying again sooner or later it will slip back in place.
When it does, turn the lower end to align with the square drive in the drive gear and reassemble it with the drive unit.
Don't over tighten the knurled nut.