Just got back from Texas. Of course the truck went into limp mode on my way back from the airport. First stop sign, I manually shifted it into first and manually sgifted through second to drive. OD light stopped flashing and the granny magically fixed it self. Or do it seemed. Drive fine the rest of the trip. But did notice torque converter felt like it was locking up coming down my driveway when I got home. I’ll be checking all the above suggestions this week. Hopefully during my time off for the holidays I can get this sorted out. I’m going to try to pull the codes using the paper clip trick, check tranny fluid level again while warm and idling, check all grounds, even run a separate ground to the tranny, and checking the RPM sensor. I’ll let you know what my results are. If only I could get the codes, that would be key. Not sure why my reader doesn’t detect them.