The 1995-97 Explorers had a differently wired stereo, those the JBL was an optional system. The Mach and Premium were not just a trim level name like many Ford vehicles have had over many years.
In 1998-2001 the Mach and Premium deck in those was not made by Ford, those are Pioneer HU's. That's very special, I don't of other Mach radios which are also Pioneer decks, but all of those 98-01 Explorers have a defect in the display board.
The wiring for the 98-01's is not the same as 95-97's, it's not a plug and play swap to move the radios to different Explorers.
I really like the Mach and Premium HU due to the OEM look huge buttons, and the nice FM quality versus typical OEM. But you have to have all of those repaired if the prior owner didn't get it done.
FYI, the later Sports and Sport Trac had a deck in them which looks a lot like the older Mach, but it has a changer inside it, six CD's I think there are. Those are grey on the face instead of black, and of course they have a clock button. The Mach and Premium both have an RDS button instead of the clock button.