I'm trying to fix the speedometer in my 68 mustang. The speedo cable in it is cooked. It was too close to the headers so I'm trying to replace it. However I'm confused because everything I see online tells me that I'll need to get a speedo cable along with the correct driven gear. When I go into the parts store they try to sell me a cable that has a different end. It looks similar to a worm gear. I guess I'm confused because the one they are selling me doesn't look like it will pair with the gear in the transmission. The transmission is a RUG-E2 toploader 4 speed and the drive gear inside of it has 6 teeth. Any help is appreciated. Thanks
-Wyatt

 

Here is a listing of the gears in the transmission. The gear on the cable is held on by a clip.

 

is there any reason why you can't take the gear off your existing cable and put it on the new cable?

 

 

In addition to the already existing confusing facts, some transmissions had the hole in the tailhousing above the output shaft, some below it. That means the angle of the cable gear is different between the two types. Note the ones shown say "left tilt"; others were "right tilt". Use of the wrong tilt ate the cable gear, but usually not the transmission gear, which was more difficult to get at. Morever, some transmissions had the transmission gear mutput shaftachined into the shaft itself. To change number of teeth required changing the output shaft. I believe AODs were like that. imp

 

The gear is held to the cable with a clip. You can see the slot in the gear in the pictures. If your cable worked, but when you pulled it out does not have a gear, the clip must have come off and left the gear in the transmission housing. Hopefully it is still in position and you can pull it out. If not it probably fell into the case and should be removed.

If the speedometer never worked, you may have a different problem. We had a 67 that someone put a 89 302 from a bronco and used the Bronco Tail shaft housing with the original 67, 3 speed. The Bronco had a speedometer hole near the back of the tail shaft where the Mustang gear is near the front. So no speedometer. Ultimately put in an electronic sat-nav speed sensor, since we had updated the dash to electronic instrument.