Hi guys I have an issue with my trans. 2000 f150 XLT 7700 with 5.4 was driving 2 days ago stopped to check out a fishing spot for me and my son got back in my truck and it didn't want to shift out of 3rd. I did notice while limping it along the OD off light was flashing. Yesterday pulled the dipstick and fluid was just over full cold. I did notice if I start truck immediately turn od off it shifts on then once I'm driving and to speed I can turn it on and it's fine. On the way to work this morning it was driving good OD off light still blinking then after an t 40min of driving it started shifting hard from 1st to 2nd or not wanting to shift at all.

 

The OD light flashing is indicating a fault. You need to have it checked for codes and repaired.

 

Yep, your truck is new enough that the powertrain control module (PCM, or "the computer") records problems. Your mechanic can "scan" the PCM for codes that will tell him what is wrong with your tranny. Have it checked soon.