My speedo needle has been bouncing for a few months and it has steadily gotten more pronounced. It started at jsut slower speeds but has become noticeable at all speeds. There is a also a "swishing" sound coming from just in front of the driver firewall that corresponds to the bounce of the needle. My local vette shop tried to lube the cable while in for transmission service last week and the "bounce" is a little calmer but still there.

Do you think that I should replace the cable(s), or could it be the Cruise control transducer (I am no expert but remember reading about that causing a similar problem in a late 70's C3. This is an 1978 L-48 w/Automatic and cruise. Any advice greatly appreciated

Hi Barry
I also have a 78 SA car.
Your spedo neddle bounces because the spedo cable is dry and binding.Pull out all the cables and grease them up-this will fix the problem.Not a big job and any lubricant will do but if I was going to do mine I would use white lithium brake grease because it will last longer than it needs to.
Steve

Thanks Steve! I will try it myself. My guess is that the shop did a half way job, (didnt charge me), so the moderate improvement may be much better if done well.

Barry I took a speedometer gear out of and old transmission,took the gear off,tapped it for a grease fitting. Take your speedometer or tach cable off,screw it on,take a grease gun a couple pumps your done.Works very well and quick.
Dave

I also have a '78 SA and had the same problem. For me, it was a bad cruise control transducer. Lubing the speedometer cable or replacing it can or should be done at the same time just to make sure.

Steve hit it right on the head, pull the cable completly out, don't be shy with the grease..

Sounds to me like your shop just added a little grease to the end of the cable.

Rick

Hi gunslinger
My car has cruise control but the transducer and cable connections are gone. Any recomendations as how to restore the cruise control?
Thanks
Steve

the corvette mags have a cable lube tool..

i think i paid 9.95 for mine.. works great..

I had, a couple of weeks back, posted a thread because my speedometer had completely stopped working including the odometer. I had replaced the lower speedometer cable a year ago. I also checked that it was working because I drove the car while holding the end of the cable and it was turning fine at 25MPH. I disconnected the upper speedometer cable and spun it around with my fingers and the needle moved freely in the dash. Process of elimination I figured the transducer was faulty. I replaced the transducer (rebuilt)and the speedometer is still not working. Could the problem be the plastic gear in the side of the transmission where the speedometer connects? Could this be broken altough the cable turned at 25MPH? Does the vaccuum supplying the transducer have anything to do with the operation of the speedometer or is this just for the cruise control function? Don't know where to go from this point. Thoughts anyone?

Steve...

I guess a lot depends on how much of the cruise control system you still have. I understand it's pretty difficult to install a factory cruise control in a car that never had it, unless you buy an aftermarket system. If all you're missing is the transducer and cables, that's pretty simple, but if the wiring is gone, you may not know everything you'll need.

You may want to consider an aftermarket system.