'94 Speedometer Issues

[harriw]

Hey folks,

On the expressway on the way to work this morning, my '94's speedometer decided I was going too slow, and went from 55 up to 75 or so on it's own. Did it fairly slowly and smoothly, though much faster than if you were actually to accelerate from 55 to 75 (more like going from 0 to 20 or 10 to 30).

The speedo's always been a bit jittery since I bought the truck (170k miles now), and my first thought was just to replace the whole cable and gear assembly. But then I started to wonder if that sounds more like the gauge itself slipping? I would expect the speedo needle to fall, not climb, if the gear/cable was acting up, right?

Last question - I did a quick search on the chain store parts websites, and it looks like most replacement speedo cables available through them are just the plain cable, or cable with the gauge connection on it. Do you re-use the plug/adapter that plugs into the transfer case or tranny (the piece with the o-ring on it)? Does the cable just pull out of that "adapter," or is there another way to connect/disconnect a cable? I was under the impression the new assembly I bought would be a complete drop-in replacement for what I pulled out including the connectors at both ends, but it doesn't look like that's the case from what I've found so far...

Thanks.

-Bill

 

[adsm08]

When I put the M5 in my truck I had to get a cable from a 91 because my 87 cable was too short. I got the 72" one from napa with the plug for the gauge. There is a horseshoe clip at the drive gear that you push in on and then pull the cable out of it. The new one should just push right in and then release the clip, and you're done.

I honestly can't think what would make it start going up all on its own like that though.

 

[harriw]

Great, that's what I was looking for.

Yeah, more I think about it, the more I think the cable/gear isn't the problem (though like I said it does jitter, which I'm sure is due to an old gear/cable). I think the needle is just loose on the gauge - got to 55 (a little past center), and just fell due to gravity? Didn't go back to normal 'til I got to the red light at the end of the exit ramp - then it fell back to 0 when I stopped. I drove when we went to lunch today and it worked fine then...

Guess I'll hope it behaves, and start looking for a new speedo gauge or cluster if it starts happening more often..... By the way, can the speedo gauge be replaced alone? Or would I need a whole new cluster assembly?

Also, I just realized there's a whole "gauges" forum - my bad, I should have put this there.

Thanks.

-Bill

 

[adsm08]

I believe it is possible to remove the speedo head and replace it, its hard to get new heads though. Aftermarket might have one, Ford won't for sure, and a yard will make you get a whole cluster. I'd probably just get a cluster it you can find one.