Hi,
I replaced the speedometer cable in my '75 slant 6 dart sport. The cable matches the old one. The odometer works fine but the needle now drops below the 0 mph mark, it also bounces around horribly. I lubricated the cable and connected it correctly. Does anyone have any idea why the speed would register 25mph slower and bounce around so bad even after everything was replaced? Could the needle itself be bad? There are no kinks in the cable.
Thanks,
Dennis

Did you have problems before you replaced the cable? (i.e., why did you replace the cable to start with?) Assuming you've got the correct speedo gear, it could read slow because the indicator spring anchor has slipped, but that would be highly unusual for it to slip in the tension direction. The stop is a tang built into the speedometer head. It can be adjusted by bending the tab, but it is unlikely that this spontaneously changed either. I've seen many speedometers that start out slightly below "0" If your speedometer just started acting crazy when you put in another cable, I'd make sure it is plugged into the back of the head properly, make sure the threads are engaged properly at the trans, make sure that the adapter at the trans is turned to the proper rotation for the tooth count of the gear, and if all that is OK, I'd pull the cable from the housing and inspect it very carefully along it's length.

Good Luck,
"Dennis W"

_________________

If it ain't broke, fix it!

Thanks for your thoughts. I replaced the cable as the old one broke. The speedometer was bouncing around quite a bit before it broke, it also made a very unusal high pitched "klinking" sound. I am positive that the cable is attached properly at the trans. The needle is acting similar to the way it was before, only worse. If I drive and reach down to adjust the cable at the same time, the needle will also bounce around. I havent been able to find a sweet spot for the cable so I am sure it is not kinked. Possibly the needle is bad. I really don't understand why after the cable broke that the needle dropped way below 0 mph.
Any additional thoughts??
Dennis S

It may be that the replancement cable is a little longer then the one that broke. Try unclipping / unscrewing the cable from the speedo and pulling it back a little, to see if the bonce gets better or goes away.
If there is no change then it sounds like the speedometer "head" (gauge unit) is worn-out. To test that, disconnect the cable from the back of the unit and spin the input by hand, it should turn freely, without any resistance or stiff spots. If the needle bounces when you do this test, it is time to rebuild the speedo or find a good replacement unit.
DD