Welcome to the forums!

So the transmission is a 5R55S. They have their issues. Your best bet is to take the car/transmission to a rebuilder/mechanic/dealer and not worry about why it breaks. It could be a lot of things. Here's a couple of videos on what it could be, but again, it could be a lot of other things.


FordTechMakuLoco is a great resource on the Fords, but there's plenty of others, just look up 5R55S on the Googles and you'll find lots of information on them and the various ways they can break.

Not the answer you want, surely, but probably the best answer, which is: Take it somewhere, you don't want that pain. Hope it helps nonetheless! Good luck!

 

Thanks! I've been lurking for a while but never created a profile. I'm hesitant to take it anywhere because I'm afraid a shop will just tell me I need a complete rebuild, whether I do or not. I typically do all my own work. What confuses me with this issue is that I had absolutely no warning. I parked it in my garage one night and the nest day it wouldn't move. No symptoms leading up to the issue. No slipping or hard shifts or anything. I was thinking it could be a sensor or something. So far this is the only post I could find on any forums that was the same issue as mine. I do have a mechanic I trust but he doesn't do transmissions and I would have to pay for a tow both ways if he can't figure it out. I checked fuses and relays. My alternator seems to be operating as it should. I did try searching for the diagnosis OP was told but I couldn't find anything matching it. Unfortunately, I may need to just take it somewhere. ☹️ Thanks for your help! I'll check those vids you posted.

 

Thank you for your response. I replied immediately but I guess it wasn't approved or something went wrong.
I typically try to fix things myself but a complete teardown may be beyond me. Those videos at least give me something to check. I'm just surprised that there were no symptoms leading up to my issue. That's why I was hoping it was something simple. Again, thanks for your response!

 

I am pretty sure the overdrive sprag is the issue, here is a video how to diagnose the problem, hope this helps someone..