When mine went out it left me stranded about 15 miles From Silver City, NM.
I had it towed to the Ford dealer there. They were happy to work on it and got it right in to check.
Since I was at the dealer I let them get a Ford re-manufactured transmission. It came with a 3 year 75,000 mile warranty.
They make you replace the cooler as well, but won't let you go with an aftermarket bigger one to keep the warranty.
Cost was around $2300 out the door.
I installed a Scan Gauge after to keep an eye on trans temps, it still runs a bit hot at times, but now I know when that happens and dropping out of overdrive brings the temps down 15 degrees.