1965 Barracuda speedometer issues

[408 lancer]

The speedometer for some reason will only go up to 20mph and stays there no matter what the actual speed is.
Ready to replace entire speedometer unless there is a fix for this.
Tried new speedometer cable, etc.
Car has a 340 , later 4 speed, 83/4 rear.
Ideas before I take instrument cluster out ?

 

[Syleng1]

I had a similar issue with a speedo.
I took it apart as far as I felt possible and it was filled with grease that was very hard and useless. I used a tooth pick and tooth brush and cleaned it all out the best I could and used 3-1 oil gently on all pivot and spin points.
After a few minutes of driving it worked great.

 

[Jim Kueneman]

Send it here. He knows old MOPAR speedos.

Dicks Speed-O-Tach Tempe - Facebook

 

[cudamark]

Maybe the needle is rubbing on the faceplate? Pull it apart and see if the needle moves freely by hand.