on the od, you need a real scanner that shows data (like snap on mt2500) and a pressure gauge. when you see the scanner show OD on request, then you need to see pressure at the OD port. if you have request, verify that the solenoid is being activated with a DVOM. also measure solenoid resistance. if all checks out but no pressure, new seals will most likely do the fix. You can buy just the 2 seals right from dodge for under $10.
if that's the van in you pictures... I'd love to buy it as-is (if you were close by). I have a 1992 B150 with a 5 speed manual trans. I'd just love to have a nice conversion van with a stick.
