Update:  my assy manual does not indicate a 2 PC speedometer cable, only a 70 inch single cable. There are no indicators of a cruise control option until now.  I replaced both cables and it appears to be working OK now.

Thanks all for your help and comments!

James

Re: 1975 - L48 all power & ac read my profile for better description. 

Speedometer does not work!

How do you resolve this issue, is it electronic like the tach or cable driven?

Any videos on replacing and repair?

Thnx, James

Can you divulge any other information? Year, model would help a bunch. 

If you have a 75, it's just a cable from the tranny to the speedo.  Check both ends.  One end may be worn down and slipping.

If so, my 75' has a joint in the middle. It may be a loose connection, or the square end in it or at transmission or speedo may be twisted. Also, the speedo end is just a push fit, with a spring clip to hold it in. Check to see if it is still engaged in all areas. 

I just went thru this with my '75 Stingray Roadster.  I ended up replacing both upper & lower cables. AL is good now!

Found it was a 2 PC cable. Resolved, thnx. James

Hi, So where was your problem? Was the center joint loose or worn out? 

The lower cable was the main issue,  frayed ... the upper I replace anyway 49 years old. Gear appeared ok!