1965 with 3 spd manual. Put on new cable and driven gear. Speedometer moves if I turn the cable by hand at trans end. If I drive the car with instrument bezel removed and watch the cable, it doesn't turn. Is there a problem with the drive gear in the trans? How is this fixed?

 

if you have the wrong rotation driven gear it wont work.

4spd toploaders are left hand helix and iirc most other ford gearboxes are right hand. if you look at the gear with the cable running back along your arm, do the teeth appear to be veering left or right? does the speedo cable go into the box on the passenger side?


if it isnt inserted far enough it wont work (your girlfriend probably says the same thing )

 

When looking gear from the end teeth veer to right. Gear has markings 3-16t and dcmr.

 

also just found that cable seems to be just spinning in the gear like the square plastic shape in the tip has been rounded off.

 

was just about to say that. when you drive and the speedo cable doesn't turn, then stop and turn it by hand. it must not turn. If it does it's either not hooked inside the gear or what you just said: rounded off.
if the gear was new and you just rounded it off, then i guess the cable itself was stuck solid and couldn't be turned by gear and the weakest link gave in (your plastic gear). probably had it mounted incorrectly at speedo end ?

 

It may not be seated all the way in the driven gear. The cable may just need to be pushed in from the speedo end a bit.

For the record the driven gears from an auto will work in a manual, they will get chewed up, but amazingly they will work. I know this first hand.

 

the gear is new, so is cable. For some reason cable was spinning inside gear. I ended up putting jb weld inside. After it dried, the speedo was working again. We'll see how long this patch job works. I'll order another gear in the meantime.

 

if new gear wasn't inserted all the way,it would work temporarily,50 yards to 50 miles. problem is it strips the internal gear in tranny. Did it myself,kept stuffing new end gears in until a friend enlightened me. He did the same thing. by the way still haven't fixed mine,have to take tail off tranny and replace internal,not difficult,so I'm told!!