My first Trac was an '05 that I got new. Really the only problem areas are the ball joints, wheel bearings, and on some the transmission will hang up between 2 and 3. The tranny issue is a computer problem and not in the tranny itself. A Ford dealer can reflash it.
The transmission is also fussy about being flushed regularly. Since you just got it I'd suggest getting a tranny flush immediately and assuming you have a 4x4 do the transfer case (it takes ATF) while they're at it, although that is pretty easy (if messy) to do yourself if you get a suction gun to fill it with. If you do not flush the tranny every 30k it is unlikely to last much past 100k. The transfer case lube should be changed every 60k according to the manual but it will look like tar by 30k.
Also consider changing the lube in the axles since it's close to 100k. The Valvoline Qwicky Lube near me will do axles for $39.99 per with a suction machine. That is really the only way to do the front axle anyway.
Get a new fuel filter. It requires a special tool and is a pain in the ass to change. Mine tend to come due in the winter so I just take it to the shop I use and let them do it.
A number of people have 150,000 plus on their Explorers and Tracs. As long as you properly maintain them they will pretty much run forever.
