Speedometer quit

[dumbucket1]

Speedometer quit on my 84 k5 blazer. It has the np208, 700r4. It just quit out of nowhere while taking an off ramp. When I got home I unhooked the cable from the tailshaft and hooked up a drill and spun it while my wife watched the speedometer. She said it wound all the way up to 85.

What should I be looking for to replace then? Isnt there a little round gear in the tailshaft that probably lost its teeth? or is there something else I should be looking for? thanks

[HAULIN IT]

Dumbucket, Yes there is a gear inside the cover, it is color coded for the final ratio. You will need to match the color of the old one (assuming it was right before) you may also have an adapter box screwed on & then the cable goes into it. One thing to concider, the cable may still need replaced or lubed. The power your drill had to spin the cable may be way more than the plastic gears ability without failure. Most likely the stem where the cable hooks in will be sheared off. Lorne   

[gbskunk2006]

I ran into a very similar problem prior to starting my resto on my truck
http://forum.73-87chevytrucks.com/smforum/index.php?topic=6879.0

Since you've confirmed the speedometer and cable are working from your drill test, re-connect the end of the cable to the tailshaft BUT make sure you tighten it up as much as you can.  If the end is greasy, consider cleaning with a wrag and\or grab some adjustable pliers and give few good turns to make sure it fits snug. 

Take it for a test drive and see if that resolves the problem.

Cheers