Never heard of Explorers going through transmissions like that. Seems like something else may be wrong with the vehicle and the transmission may be the weak link that keeps going out.

 

The 2nd gen Explorer has consistently below average reliability ratings per CR, although the engines seem to be largely flawless per what's reported.

And per CR, the 04 Explorer 2wd has the worst possible rating for transmission-major and transmission-minor, interesting (since it's the same model the MPLexus301 has reported in on).