02 ranger 3.0 2wd. tranny wont disenguage or change gears on its own

02 ranger 2wd 3.0. It drove fine with no indicators, i parked it for about 4 days, now i have
issues. It Starts fine, reverses ok. If I put it in drive and press the gas, it acts like it is in a
much higher gear. It studders, bogs down and really doesnt move. If I put it in 1st, it does
the same but to a lesser degree. I can blip the gas a few (dozen) times to slowly build
speed to get it rolling, then it drives ok. Ill manually shift into 2nd and drive and it does
well. I replaced the filter, no joy,  hot/cold same story, fluid level is in the hashmarks...ive
got a check engine light and o/d is flashing, I dont reallyhave a way to get codes checked