I have a 1999 4.6 manual with smaller than stock tires and a 10 % speedometer error. Because the truck is a 1999 I thought I could use the superchips 1715 tuner to reset my tire height and cure my speedometer error, but so far that hasn't worked. Does anyone know when Ford switched form the speedometer gear to the computer? Is it possible that my 1999 still has the speedometer gear?

 

I'm nearly positive that 99 was the first year that a computer was needed to calibrate the speedo.

If you are having trouble using the microtuner to correct the speedo then maybe you should post in the computer chips forum and I'm sure Mike T. or someone else will have the info you need. A search on the subject might also turn up some useful info.

Good luck.

 

Simple way to check. Look at the tailshaft housing of the transfer case and you'll see a wire running into the case. Thats the VSS gear, if you have a computer controlled speedo that won't be there.

 

Thanks LEPEW and powerstroke, I had inspected the tailshaft area eariler and at one point was about to remove what I thought was the Speedometer gear. Before I did that I wanted to check with a local speedometer shop to see if they had the right gear, the speedometer shop said that a 1999 would have be taken to ford to get the computer flashed :-( Well I went back again and checked for the wire that powerstroke mentioned, sure enough looks to me like my problem is that my 1999 has a speedometer gear. This weekend should get some time to find out for sure. Thanks again guys.

 

can someone take a picture of where the wire is on the tailshaft? I would like to compare....what color is the wire...details please

 

The wire is located at the rear of the transfer case tail shaft at the 9:00 o'clock position. Its got the plastic flex coil protection so it's hard to tell exactly what color it is. I just pulled mine off thinking that I would find a speedometer gear, but the gear wasn't to be found, just a black sensor so I guess I'm back to square one.

 

Here's a picture of the tailshaft with the VSS centered. To remove, you simply remove the nut (10mm) and pull the assembly straight out. Changing the VSS gear is simple. It's easier if you unplug the assembly from the wiring first. The gear itsself is held on by a simple metal clip that's removable by hand. Just pop off the clip and the gear comes off easily. The whole thing took me maybe 10 minutes to do. Hope this helps.

https://www.f150online.com/galleries...3541-50909.jpg