68 barracuda speedometer issue

[rlipp69]

My speedometer is jumping around and when when it holds its way off. Was going 35 and was showing 50 on the speedometer. Any suggestions fixing the problem.

Thanks
Ralf

 

[halifaxhops]

Try to lube the inner drive cable first.

 

[4spdragtop]

Try to lube the inner drive cable first.

Yep. Also check connection in tranny/speedo gear.

 

[halifaxhops]

If that does not work look at the drive gear in the tranny there are settings on it for the tooth count, I had one slip and the gear was intermittently driving. If all that is good look at the spedo itself and make sure there is no corrosion on the back. I will look for a pic.

 

[RedFish]

Speedometer issues often appear when the climate changes to very cold. Clean and lube cable/sheathe could cure it.
To poke more grease in that square drive hole at back of the instrument without cleaning what is in there out good first can do the instrument more harm that good.
On the other hand, if climate change can be ruled out and If the cable has been applying pressure to that input to the point that parts inside the speedometer are now colliding... The damage is done. Instrument service will be needed. Good luck with it.