Speedometer cable question

[jason999]

Hello,

I installed a new speedometer cable on my 1966 C10 with original gauges and a turbo 350 transmission. I greased the cable and checked for binds but it still made a ridiculous kind of honking noise at times when I picked up speed.

Yesterday, I unscrewed the cable thumbscrew from the gauge slightly (2 turns?) and the noise stopped!

So I am thinking that the inner cable is slightly long. At first I was going to add a rubber washer inside of the thumbscrew that attaches to the gauge. I thought that I could tighten it down and still leave the space that it seems to need.

After thinking about it, I believe that I could probably just disconnect the cable from the transmission and cut a very small amount off of the cable. I would obviously trim from that end because the gauge end has the fitting. I believe the cable is a little long at the transmission end and it is forcing more cable out of the gauge end than it needs, resulting in the noise.

Does that sound correct?

Maybe I could just leave the thumbscrew a little loose but I would rather tighten it.

[curvedglass]

Never gave that a thought. I replaced my cable twice and I believe that might have been the demise of my freshly rebuilt speedometer. Original speedo was messed up. Changed the cable and no help. Heard that noise too. Changed the speedometer out for the rebuilt one and every now and then would hear the groan. Got a new cable and things were fine for just a few weeks then - bang- the speedo starts flailing about and the odo stops ticking. Sent it out for another rebuild. When it comes back I may try what you are thinking of doing. I will cut the first new cable as a test.

[jason999]

Originally Posted by curvedglass

Never gave that a thought. I replaced my cable twice and I believe that might have been the demise of my freshly rebuilt speedometer. Original speedo was messed up. Changed the cable and no help. Heard that noise too. Changed the speedometer out for the rebuilt one and every now and then would hear the groan. Got a new cable and things were fine for just a few weeks then - bang- the speedo starts flailing about and the odo stops ticking. Sent it out for another rebuild. When it comes back I may try what you are thinking of doing. I will cut the first new cable as a test.

Before, I might drive off and have no noise. When I accelerated more the noise seemed to start, but it didn't do it constantly. I have mostly just driven around our neighborhood, so I was probably going 20-40 mph. The noise was super aggravating and it was sort of like a groan. It was a kind of spinning maybe whining, but not shrill, kind of noise. It almost sounded like a drawn out goose honking noise or maybe more like a kitchen blender. I have no carpet or insulation in the truck yet, so that could have been a factor but I felt like people outside of the car could hear it. It did it quite a bit and I really wanted it to stop!

So as I was driving around the neighborhood yesterday, I put my hand behind the dash to see if I felt vibration in the cable. I thought that I might unscrew the cable from the gauge cluster and leave the cable in the same position to see if it kept making noise. I wanted eliminate the speedometer from the equation to see if the cable could be in a bind.

Anyway, as I was driving I decided remove the cable so I turned the thumbscrew a few times. Then I thought driving down the road, bent over and reaching behind the dash was a bad idea. I thought that I should pull off the road to finish loosening it so I stopped messing with it and drove away. To my surprise, the noise stopped!

If you have a noise, I wouldn't start out by cutting the cable. Just loosen the thumb nut a few turns and see if it subsides. It would be great if this information helps someone else. The noise was driving me crazy

[geezer#99]

Don't use grease on the inner cable!
Use oil!
WD40 works just right.

[63burban]

Use graphite on the cable. Yes the noises are made by the speedo itself so it should be cleaned and lubed. but the cables could be long also, I had the same situation in my 65 pu. I cleaned and lubed the speedo head and clipped the cable about 1/4 inch and it works great now. Use graphite on the cable as it will not collect dirt or gum up.