Speedometer/Odometer Intermittent

[nyuk98gt]

2badazzstangs,

Ugh! The only think that I can think of is that the speedo motor on the gauge cluster board is dead or dying. But, please beware of my sketchy electrical skills before you try to find a replacement panel. It's been too long since I had my instrument cluster out (I took off the luminescent gauge overlays) so I do not remember the back of the board. There is a tech article on this forum that shows how to replace the odo gear and I am pretty sure that the poster included plenty of pics and one shows the back of the electronic panel.

***edit:
Here it is, by Jinx .... (in the "4.6 Tech Important Threads" thread stickied at the top of the forum):
http://www.stangnet.com/mustang-forums/605742-pictorial-guide-odometer-gear-replacement.html
***end of edit.

When the VSS is out of the trans and you spin it with a drill, it should generate an AC signal (yup, alternating current). If it does then the drive gear in the trans may be worn or the speedo motor on the instrument cluster is tired. Let me check my Ford shop manual (this evening) to see about troubleshooting the speedo.

Sorry to hear that this is still a problem. I was sure "we" had this sorted out.

Chris

 

[2badazzstangs]

2badazzstangs,

Ugh! The only think that I can think of is that the speedo motor on the gauge cluster board is dead or dying. But, please beware of my sketchy electrical skills before you try to find a replacement panel. It's been too long since I had my instrument cluster out (I took off the luminescent gauge overlays) so I do not remember the back of the board. There is a tech article on this forum that shows how to replace the odo gear and I am pretty sure that the poster included plenty of pics and one shows the back of the electronic panel.

***edit:
Here it is, by Jinx .... (in the "4.6 Tech Important Threads" thread stickied at the top of the forum):
http://www.stangnet.com/mustang-forums/605742-pictorial-guide-odometer-gear-replacement.html
***end of edit.

When the VSS is out of the trans and you spin it with a drill, it should generate an AC signal (yup, alternating current). If it does then the drive gear in the trans may be worn or the speedo motor on the instrument cluster is tired. Let me check my Ford shop manual (this evening) to see about troubleshooting the speedo.

Sorry to hear that this is still a problem. I was sure "we" had this sorted out.

Chris

Thanks Chris,

I was pretty sure this was the problem due to the old gear being all chewed up. Originally before looking at the gear I did take the cluster apart to check the speedo gear. The speedo gear looked great so I put it back together. Then I looked at the trans gear. What's weird to me is that it's intermittent. I drove 40 miles today and it was fine, but on the way back after about 15 minutes the speedo started acting up again. I could be cruising at 75 on the highway and the speedometer will bouce +/- a few miles an hour and then work its way to zero after 10 minutes or so. It seems to me that this is a mechanical issue most likely, not an electrical issue. I almost think a gear is slipping somewhere. So the 18 tooth gear is turned by the drive gear in the trans. How hard is it to get access to this drive gear?