speedometer bounces excessively

[ff6849]

 I installed a complete set of Autometer gauges, what would cause the speedometer to bounce excessively, it is a mechanical speedmeter and connected to a  727 transmission.

[Jamiez]

I would check the cable.  It might need to be lubed or it might have been damaged (partial melting against an exhaust pipe is common.
you can disconnect the transmission end, and connect it to a drill and spin it if you need to bench test it.

[_Russ_]

Mine was the same. Had a look underneath and it had burnt through from the exhaust. It eventually stopped working. Replaced with a new one and was good to go.

Mine only bounced between 40-60 mph. Either side of that range and it was fine.

[dodj]

I would check the cable.  It might need to be lubed or it might have been damaged (partial melting against an exhaust pipe is common.
you can disconnect the transmission end, and connect it to a drill and spin it if you need to bench test it.

But curious. Can you damage the speedo if you spin it backwards?

[Jamiez]

Maybe if you really gun the drill you could.  If you go slow it shouldn't be a problem.  I've spun mine both ways trying to get everything set.  Usually I just want it to read somewhere around 5-20mph just to make sure I have it connected okay.