2001 transmission/TRS question

My wife's van has had an issue twice in the last couple weeks, both times when it was raining.

The "OD Off" light flashes and the information display says "Check Transmission".

The fluid level was down to the bottom hole on the dipstick so I topped it off but that didn't change anything.

I searched around and came up with the TRS. That would explain the lights, but would it also cause the trans to shift funny and the engine to nearly stall when stopping at intersections?

Feels more like a TCC problem to me. I made an appointment to drop it at the dealer Friday morning but I'd like to be armed with a little knowledge before I go.

Also, I had a fluid flush and fill with a filter cleaning/replacement at approx 70k miles and I'm at 160k now.

The TRS can cause all kinds of strange problems.
The dealership should read the codes and see if there is any other item that is acting up.
The fluid is supposed to be changed every 30K miles in normal service.
I suspect that few people do this, but that is the change interval.
You could drop the pan and change the filter say, every other time.
Fresh fluid is critical to modern transmissions.

Wow. Didn't realize the service interval was that low.

The dealership did the repair outlined in TSB 05-23-7 which relates to water getting into the control module plug.

Seems OK for now. I expect rain tomorrow or the next day so that will be the real test.