I just thought I'd throw this out there...
When you have transmission issues like this, before tearing into valve bodies and replacing solenoids, get a can of De-Oxit and find the white connector on the driver's side of the transmission, just below the gas pedal.
This area seems to breed corrosion and those little pins need to stay clean -- they transmit signal between the ECM and the valve body. If they can't talk openly, then strange things happen.
Carefully pull apart hte connector and look around in there with a flashlight. I bet some of the pins have green gunk on them. Give both sides a good spray, let them dry for an hour or so, coat the outer seal with dielectric grease to keep more moisture out, and see if that works.
It's helped me twice so far!