1996 has 3rd gear only

I bought this 96 Riv and the PO claimed an exhaust leak was causing it not to run well. I have gone over it and it seems that the tranny is the culprit.
It only runs in third gear. The scantool will show the pcm is sending the correct info to the tranny- I take off, it shifts one, two, three, then shows the third gear config on the solenoids and stays that way. I have to turn the car and restart it and it starts the cycle again, once through and stuck in third. Physically, the tranny is NOT shifting, it goes 0-70 in one gear.
I have dug around and found a wiring diagram and see that pin a is 5v and e is 12v, I have the 5v but no 12v to e.
The computer seems to be communicating with the tranny. How do I trace pin e? I can't find much on the wiring on this thing and my Alldata disk with these GM's is scratched . Can I try providing 12v to this wire?
Thanks!

3rd gear is the default setting that the PCM commands the tranny to when it detects a problem. You will absolutely see the correct solenoid values when this happens (OFF/OFF), because it's stuck in 3rd.

You need to pull codes (if any) and go from there. Almost anything could be wrong with it. The 4th gear shaft could be stripped, which would explain why it's fine every time you restart the car. Once it gets up to speed to shift to 4th, the PCM detects the problem, and shuts everything off until you restart it.

If you're referring to PIN E of Connector #1 (PNP Switch), you will only have 12V on it in PARK or NEUTRAL. That's the Starter Enable wire....