Those Explorer transmissions are based on the Ford Pinto Design believe it or not. And in 1997 they went to a 5 speed system using the same internals. First American car with a 5 speed transmission, but at a big price. The problem there is: the already poorly designed internals are being used at twice their duty to create 5 gears. So, your 100K trans has 200K on many parts. I was told that when I got my Explorer by a good used car dealer.
They also specify a lifetime fill interval for normal service, and many will never change their fluid. My Explorer then had a 30K interval. The 4R55E isn't perfect but no where near the failure rate of the 5Rs.
2002 made the problem even worse, not hard to find information about that on the web.
A ford reman may be a good idea, hopefully the issues with the servo bore are addressed. You have a nationwide 3/36K warranty too.
The explorers are heavy vehicles and people tow with them. They should have all had 4r70ws, like the V8 96-00s had. They are often salvaged out of 250K explorers, fluid changed, and back in service.