So my speedometer on my 67 isn't working, I changed the cable, and turned the cable and the speedometer moves, so I know it's not that. The little plastic gear looks fine when I pulled it out too, so I think it must be whatever is inside the the transmission that is bad. Does anyone know anything about this, or how to fix it? Thanks..

 

that's a new one to me. you say the gear looks good also? there is nothing sripped looking at the gear in the tranny?

 

look at the gear from the side and see if there is a dip in it, it doesnt have to have striped teeth on it to not work
to remove the one inside the trans , you need to remove the tail housing and there is a little clip the holds it in place, also make sure there is no slop in the hole where the long plastic piece goes through theholder.
when you turned the cable and the speedo moved did it just jump a little? try using a slow drill hooked up to the cable and spin it to see if the needle moves smoothly

 

The speedometer moves smoothly when i turn it. I'm assuming that when you pull the plastic gear out of the side of the trans that you should be able to put your finger in the hole and feel the gear on the inside, and I don't feel anything in mine. That's why I think it might be an issue on the inside.

 

you can look inside with a flash light, there should be a gear inside