I think so too, but why do I still get the odometer working and the speed signal through the OBD port when I disconnect the sensor on the axle?

This IS the VSS I'm disconnecting, isn't it?

 

Yep, that's the VSS. I don't know what supplies the signal for the ODO if it still works with the VSS unplugged.

I'll do a quick search for the ODO and see what comes up.

EDIT : In this Thread I found a reference about pulling a plug on an automatic that will disable the ODO but it will also keep the tranny from shifting. They did not say which plug because it is illegal to tamper with the ODO. I would guess it would be the OSS sensor. But I don't know if the 6 speed has an OSS sensor.

 

I'll have to crawl under and search around the trans to see if there is an OSS sensor on this thing then do some testing with it unplugged. There's a few speedo shops in the area I can try too. Either that or a used cluster from somewhere. I would still want to transfer the mileage. It's pretty low on this truck.

 

Took my cluster in to the local speedo repair shop. Have a good reputation from what I can find out. I was told when I called that if it is a coil type movement, a new cluster is the only way I can go. If it's a newer stepper motor movement then they can replace just the stepper motor.

Sure enough, when I brought it in, it is a coil movement. The reason you can't swap those movements is because when you pull the needle off, it unravels the internal of the coil movement, instantly destroying it. Apparently they don't fail often, but mine did. They told me that I can bring them a cluster and they can match the ODO for $75.

All the junk yards charge $150 for these and they're around $400 new from the dealer.

I found one used on ebay for 78.55 + free shipping:

Speedometer Cluster Gauge 1999 Ford F-350 Super Duty - eBay (item 250709960368 end time Nov-05-10 10:42:06 PDT)

It's on the way.

Before that, I took mine apart to see if there was anything obviously wrong internally. All looks good in there, so I went to see about manipulating the odo:



The trip ODO is easy to change. In between the numbers the gears are accessible with a thin probe. It is resettable without damage. The main ODO is different. The number wheels are set right next to each other with no gear space, and are much more resistant to being spun. It seems damage would be caused one way or the other...

My truck has only 108K on it and the new speedo will have 214K so, I really do want to roll back the ODO to match actual mileage:



Anyone know how I can do this without causing damage? I'd rather do it myself than pay someone the same amount I bought the cluster for.

If you know, you can send me private message to avoid spreading it to everyone.

Thanks.

 

Speedo shop matched mileage on my new cluster to my old one. Everything is working finally.

Now when I get some spare time, I'll pull apart my old cluster's odo section and see how they did it. At least I don't have to worry about wrecking it