The Stovebolt Site Forums The Shop Area General Truck Talk Speedometer Rattle and Jumping when Cold

I've noticed the last few times driving my 52 pickup that the speedometer makes a rattling, grinding noise when it's cold. The speedometer will jump up to 70 and drop back down to where it should be. This seems to go away after the truck warms up some and I rarely (if ever) hear it or experience this when the temp is warm outside. I read somewhere that you need to lubricate the cable or something but it wasn't very clear. Do any of you fellow bolters out there have any experience with this or advice? Thanks in advance (pun intended).