I have an 04 Ford Explorer Sport Trac, and my manual says 150,000 mile ATF change. One got done at 46,000 miles, but haven't since. The first generation Sport Trac(mine) are on the Ranger platform and it would have the same tranny as your 02 Ranger, the 2nd generation Sport Trac are on the same platform as the Explorers. Even if the transmission look the same between the two vehicles, variations are different. My understanding is those transmissions in those years are not reliable. Which is why it broke anyways.
One thing I found is that people get confused about what the OM said about ATF OCI. There was a transmission in heavy duty vehicles that said, 30,000 miles, the rest are 150,000 miles. They thought all were 30,000 miles. Are you sure your 02 ranger didn't say 150,000 miles?