I have wondered if changing out all all the solenoids might fix my problem. one day I was going down the highway at 70 and I lost drive. I managed to get off at the next exit and it had just enough left to barely get it on a trailer. I saw one of your posts about how this is a known weakness on these, and since this happened all at once I just realized it may just be I need to change the solenoids. it has over 100k miles, but mostly highway since at the time I was driving 77 miles one way to work every day. I changed the fluid and filter religiously on the transmission.
It could be a lot of things, really it would be best for a transmission pro to check it out. When I had a similar problem it was caused by a band breaking due to metal fatigue.
it affects all the gears, isn't there a solenoid closest to the front that controls just the fluid pressure? rather than give up the car for scrap, and they have a reputation for that solenoid going bad, I might be willing to try that first, line pressure solenoid
Our resident transmission guy @dan might know about that for sure. Although I'm not fond of the parts cannon approach, if the part is not expensive and you can replace it yourself you really have nothing much to lose by trying.