Speedometer "Bounce"

[Mallinson1 <Mallinson1@domain.elided>]

I installed a new speedo cable last night and last night it worked great.
Today, however it bounced so wildly at speeds under 30 that I couldn't tell
what speed I was travelling.  The bounce is accompanied by a "sching, sching"
sound that resembles coins in your pocket.  I was careful not to kink the
cable and it is routed the same as the old one was.  There is a 4" diameter
bend just before the cable passes through the firewall to the cab.  I cleaned
the old, gunky receptacles and carefully lubed the cable in accordance to the
directions.  Suggestions?

Thanks,
Steve Mallinson
Seattle, WA
62 C100 PU, no heat or defrost