Not shifting and no speedo
Hey, I have a good idea what is wrong with your truck. I have experienced the same thing with my 95 daily driver until it finally wouldn't go past second gear.
I had tried new VSS and many other ideas from here and from mechanics advice.
Here is what solved my problem:
1st make sure your connection is secure at the VSS.
2nd If it is trace the two wires from VSS to PCM (located under glove box) wire loom should run under hood and tuck between A/C coil and passenger front fender. The wires will be with approx. 50 or 60 other wires. But don't worry..... at least in my 95 there were only 2 wires that are twisted into a "rope" look out of the whole bunch. They are purple/white and Green/black on 2 wheel drive (light green/black and purple/white 4 wheel drive).
3rd Cut old wires and abandon.
4th replace, reroute, plug in and make water tight connections (lots of black tape and butt connectors)
5th Drive and enjoy! Wires get beat up and lose coating over the years and can't send the signal needed.
If I get enough interest to this seemingly huge problem, I can post a block of pics and video to you tube. You decide.