I decided to replace the transmission fluid myself just recently, at 127,000 miles as I have complained about this problem each time I took it to a so called "reliable " transmission shop for a filter and fluid change.
It turns out that the three previous times they charged me for servicing,nothing was done because I found the original gasket on the pan.
What a buncha Crooks.
The fluid was burnt,but no filings. It was kinda dark and thick,but after changing the fluid with a recommended fluid for high mileage vehicles it is now shifting alot better. I saw the thread about using seafoam trans stuff and I just added 1/2 a bottle. I will let it circulate awhile and then change it again. I think it is pressure solenoid journals are clogging. It is fine when it is cold and then acts up after it gets hot.
I haven't yet tried leaving it in third. I will try that next. It does seem to happen only in third gear with light throttle.