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Ford 4-Speed Toploader

I have a 1972 Ford Mustang, 351C-4V, 4-speed toploader, Hurst shifter. The speedometer does not work (at all) so I replaced the speedometer cable and reused the cable driven gear inserted into the extension housing. Still doesn't work. I can feel the output shaft in the extension housing with my finger through the speedo-gear hole. I can't feel the drive gear on the output shaft. Is it possible that it broke off and is in the bottom of the extension housing? Could such a gear (plastic) just break off? If so, what's the best way to replace it now? Does the whole transmission have to be removed or is it possible to somehow remove the extension housing to expose the output shaft?

Reply to
Joe
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FYI: Some good information on Toploaders @

Reply to
Grover C. McCoury III

I don't think you have an internal speedometer drive gear problem. The teeth on the internal speedometer drive gear run almost parallel with the sides of the gear. Look at the gears in these pictures.

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Although I've only removed the tail shafts after I have removed the entire transmission from the car, I suppose it could be removed while the transmission is still bolted to the engine in the car. Are you sure the speedometer cable is not turning? Are you certain it is inserted all the way into the back of the speedometer? That can be a real bitch sometimes. I would confirm these two items before I pulled the tail shaft.

Reply to
351CJ

Yep. The speedo cable is turning. I can actually spin the driven gear on the transmission end and the speedometer moves (at least a little). When I insert the cable into the transmission (which should mesh with the gear), I can still spin the opposite end of the cable (at the speedometer side). I don't think it is supposed to spin when inserted into the transmission.

Reply to
Joe

You are correct. You said you replaced the "driven gear" right. Not certain but I thought that the drive gear is a steel worm gear. Points back to the driven gear unless there is a shear pin that has broken.

Reply to
Richard

They are both plastic, look at the picture in this link.

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Reply to
351CJ

Plastic it is. Being plastic would seem to allow for it to break and/or otherwise not be locked into position. Looks like there is a slot for a key. Something has to lock into place. Can you reach in with your finger and rotate the gear?

Reply to
Richard

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