I'm not sure why you're posting here, as this is mainly an Isuzu newsgroup,
but I'll try to help. First, you have to eliminate the possibility that
someone overfilled the transmission - either by checking the fluid level
warm (or cold, whatever your manual says) and seeing what it is. If it's
overfilled, that is probably your problem. If not, you may want to see how
the fluid looks first to see if it's brown and smells burned... if so,
you'll need a transmission rebuild. Finally, do a transmission pan drop and
check to see what condition your filter is in, although that won't cause
fluid to come out your filler pipe, but it will give you a chance to drain
and refill the transmission with the right amount of fluid and you'll have a
clean filter, which you need to do anyway at 70K miles.
Hope this helps.
r/
Steve