you can put a cable end in and spin it with a drill motor, reverse will make it register forward, can't tell anything turning by hand .... it may be that there's enough wear to let the mechanism rattle around a bit, in which case you need another - not adviseable to use a lubricant in the speedo, it'll gum things up sooner rather than later, but if you take it apart you might clean out the 50 years of accumulated junk and find it works fine
Bill
