During my test drive, I never got the trans to shift from 3rd to 4th. It wasn't a "slip", it was a "no shift". Seemed odd because it shifted fine in all the other gears. No slips or flares.
Could modulating pressure still be a culprit in light of, otherwise, normal shifting?
Also wondering if the 3/2 valves could be involved? I did notice the small, crescent shaped levers on the valves are worn pretty thin (black plastic cover was missing).