[Windstartled]

Hmmmm... that's a tough one. If the 95-98 VSS is physically different from that of the 99-03 Winnies and does not operate on the same principle then the computer needs to be instructed on how to manage the data it is receiving from the VSS. I don't know if it is possible to reprogram an older computer to handle data from a newer sensor but it's worth asking around.

"VSS" is somewhat of a misnomer at Ford because it doesn't sense the vehicle's speed, that task is actually performed by the rear ABS sensors, which feed both the VSS and the speedometer. The VSS, as far as I could tell from reading the appropriate sections of the original Ford shop manual, monitors the speed value obtained from the rear ABS sensors and sends this data along with certain transmission parameters to the computer which then processes the data and manages shifting accordingly.

At least that's how it works on the 99-03 models. From your description of speedometer issues you appear to be dealing with a bad communication between the VSS and the rear ABS sensors. If I were you the first thing I'd try would be installing 99-03 ABS sensors and see what happens. The sensors are cheap so the financial risk to you is very low.