So fellas, In my efforts to get a speedometer working in my 54' Chevy 3100 (original 235 and 3-on-the tree and transmission), I've come across a few things.

1) Hoping for a quick fix I thought it might be the cable... its not. Old one spins just fine.

2) took the gauge itself out... it was all sorts of frozen up, but I got it freed up and it spins and reads (when hand turning the gauge/cable)

3) Took it for a spin and it still doesnt read the speed... so my next guess is that its the speedometer gear IN the tranny.

That what it sounds like to you? Whats involved in getting this fixed? Can I do it while the tranny is under the car? Any and all help will be greatly appreciated!