1995 Windstar won't shift after running a while.

1995 Ford Windstar will shift when first started and then won't shift after it has been running a while. If it is shut off and then restarted it will shift for a while and then again stop shifting. Again another shut off and restart will make it shift. It is as if it is losing pressure after running a while. The fluid level is OK. I read somewhere that this trans has some sort of pressure compensator that changes pressure depending on temperature. I wonder if this is somehow related. I have a scan tool and there are no codes and the OD light is not flashing. It would be better to fix something simple rather than rebuild the transmission for more than the van is worth.

I do not really know what to suggest....other than the Transmission Range Sensor (TRS) aka Neutral Saftety switch.
If this happens again....try shifting into '2' and see if that helps.

Otherwise, there was an issue, particularly on the '95 with the pump shaft....however, others have posted that a sign of this is a high fluid level (although you could be slighly low to start with...and the issue puts you up into the normal range).......but at this point....I am only guessing.