Well, not so good.
I will try to make it simple, good luck!
I took the mode switch out and rebuilt it (the DIY write up is pretty much right on) You can remove the connector from the metal plate, it is a 2 piece unit that slides off of a plastic back. These become brittle break easily, just do not break the lock on the main wire harness with the water seal. I took a bunch of tools out there and found I just needed a 1/4 ratchet with a short/long 10mm socket for the 2 switch bolts, 14mm wrench and pliers for the shift linkage section, and a pair of cutters for the tie wrap, screwdriver for connector locks.
The DIY picture says it all. Crusty, funky and old. cleaned with electronics cleaner and a shop rag. Careful with the fingers that slide on the silver PCB traces. Cleaned, lubricated, nicely reassembled and reinstalled.
There is a small vacuum hose with what appears to be a breather end.
I replaced the 2" section of hose because it was split.
I had a bad feeling when I took it apart because it is very simple. Going from full throttle down to barely moves within 40 miles would make more sense if something was clearly broken inside of it, the contacts were more worn etc. Or if the shifter linkage was sloppy or the adjuster bolt came loose, etc. All solid. ( No A/T fluid in unit from leak)
There is a diagram in the shop manual, it is possible that a wire broke off one of the switch pcb board contacts, you can check the connections with a ohmmeter.
The fluid is not perfect, but it was not way low or burned up. The pan gasket has been seeping but does not stain the driveway. I think it is a pressure issue. There is a small slope on my street, I drove up on it a few times just with enough throttle to keep it steady. Will start to idle up then roll back. (in reverse too) Turn it off for a minuite and it will go for a short time again.
There are no MIL or TRANS lights and my basic scan tool tells me nothing. I think I am going to have to call for a tow and get bent over a barrel. I need a lift and a good scan tool. It is just beyond what I can do here when I need the darn thing. No A/T diagnosing experience. Bummer.
I will put down my box of tissues and hand the keys over for now.
Anyone else have a last ditch idea???