Spedometer Problem

[Jarrad]

The speedometer in my F350 is not working no odometer when I remove cable from tranny and turn gear speedometer works. Gear on cable looks good, when I insert in tranny I cannot turn cable so I assume it is engaging a gear. I removed instrument panel and drove truck with cable installed in tranny and cable does not turn. I bought a new complete cable but gear did not come with it nor did mine fit the new one. I replaced the cable only but same results.

At this stage I do not want to disassemble the tranny. I need to get this safetied. Any Ideas?

[19674x4]

sounds like the gear in the tranny is shot, i would pull it out and check it out. Because if you could spin the cable by hand and the speedo works, then it has to be in the tranny

[Jarrad]

Would you consider this a big job or is there an easy way to get at that gear?

[Jarrad]

Here's a photo of the rear end of my drive shaft it looks like a problem occurred here or does this look normal ? Could be when this repair was made the speedo gear was compromised ?

[fordman]

to get to the gear i think you have to just take off the tailhousing of the transmission. i haven't messed with that many ford transmissions. and i haven't messed with any others for quite awhile.

[19674x4]

Here's a photo of the rear end of my drive shaft it looks like a problem occurred here or does this look normal ? Could be when this repair was made the speedo gear was compromised ?

I don't see where it comes out of the tranny, could you make the pic bigger. Or have you found where it comes out of the tranny? It looks normal, your u'-joint looks fine. the gear should have a threaded collar on it to attach the cable to. If it's a 4x4 the cable is on the output shaft of the t-case. follow the cable out of the firewall all the way to it's destination.

[FORDification]

I think he was referring to what appears to be a rewelded driveshaft, probably shortened from a different application. No, I doubt that had anything to do with the speedo problem. Those plastic drive gears just wear out over time, it's not uncommon....especially if the speedo cable wasn't adquately lubed and it siezed up, taking out the plastic drive gear.

[19674x4]

wow, i just noticed that shortened driveshaft, good eye keith

[Jarrad]

Is that spedo gear plastic inside the tranny ? I have had a look at the schematics for the tranny and I am going to have a try at removing the rear housing. Im not shure if I will find a new gear/gaskets but I will check with napa today.

[fordman]

the plastic one comes out with the cable i think. inside the case is a metal one. that runs the plastic one.

[Jarrad]

I replaced the gear in the transmission for $100 after an unsuccessful try at fabricating it on my lathe. Speedometer works now although very jumpy ?

[kid]

Jumpy? Sticking cable or missing teeth on the plastic gear. Each application gets a different plastic gear on the cable. The tranny gear stays the same across many models.

Plastic gears are also color coded for different gear ratios on the older Fords.