Thanks for your input...I finally have an update!

Had the car towed to a transmission guy-- at least he's done transmisions for the past 30 years exclusively.

I suggested the PNP switch (I actually supplied him with one), but he never went so far as to put it in.

He hooked it up to diagnostics, but found no codes (I also had checked with my scanner)

He drove it around for a couple of days (it seems to be running now) in an effort to produce some sort of code... to no avail.

He told me the existing PNP switch was working fine, but he suspected that the filter was clogged, and it wasn't a serviceable tranny. He aslo said there were particles in the fluid (had a blue-brown look) I had flushed this myself using bay13 method about 15k miles ago. He also said he heard a suspicious noise from the transaxle.

I had him flush it, then drove it home (70miles). It seemed to shift fine, except for what I'd describe as "a bit" of hesitation between 2 and 3. I figure I'll drive it... if the tranny is on the way out, it won't be long, but is it possible I just overfilled it/ it overheated?!

Oh well...