Speedo Cable

["Tyson Sherman" <tsherman@tecinfo.com>]

I tried (well failed) to change the speedometer cable
in my 76 B today.  I tried turning the nut where it
screws into the OD, but the whole assembly moves,
so the threads don't loosen.  I can see another
piece moving (perhaps what the manuals call the
speedo gear bearing).  Should this be difficult, or
is the speedo gear (I think plastic) worn out?
Thanks,
Tyson Sherman
<http://www.tecinfo.com/~tsherman/index.htm>