A 1990 should be an AOD (non electronic). According to what I can find, AODE started in 1992, and 4R70W was phased in to replace it in 1993 and 1994, which means AODE (not 4R70W) wasn't around for very long, and not in 1990.
So what do you really have? AOD (original transmission in 1990), or AODE (1992 or 1993 or maybe it has been retrofitted to the earlier vehicle)?