Does the check engine light come on while driving? If so, you need to have it tested to see if it a transmission related fault that is causing the check engine light to come on. If light is not on, you need to check basics like transmission fluid level and quality. Some of these vehicles were recalled to have an additive to transmission fluid added, if your vehicle is covered by this recall and the recall was not performed, this maybe a cause of your symptom. You can go to a dealer an have the vin # run to see the recall is still open. If fluid level is correct and appears to be clean, I would recommend having it checked out by a qualified dealer or repair shop. There maybe a Technical Service Bulletin,(TSB) for a software upgrade, which may cure your problem. This software upgrade requires the proper equipment to carry out, so you need to ask your repair technician if they have these capabilities. Good luck.
I had the same problem. The problem started with hard shifting at low speeds, and only got worse with time. I suggest that you Google this problem on-line and you see the numerous people with the same prob. Ford did upload program changes, but that was only a short term fix (the problem returned only worse) After discussing this with Ford with no resolution, I talked with a local transmission shop that I trusted. His initial statement to me was that he has made a living off of Ford Explorer transmissions. The problem seems to be with the servo valve internally...they bored and resleeved for a new valve. The cost is about $2500...Ford wanted $3500 for a new transmission, but would only give me an out of sight, out of mind gaurantee. Hope this helps..