speedo cable problems

Does the speedo input socket spin? Check to see if it is locked up. Did you buy a new cable and jacket or cable then inserted into the old jacket? Could have a kink or bad spot in jacket. If it is an old jacket is the inner lubed up, especially if it has been sitting for a while. Also check you pinion gear at the tranny. Is it broken or not properly set for the correct engagment? I ended up buying a repo cable and jacket off of fleabay, seem like an easy way to resolve speedo cable issues. Good luck.
Andy