That's exactly right - you can totally control an /E (or I believe the 4R70W also) with that box, line pressure, up and down shifts, etc. Check out the "waterbox archives" at
www.alternativeauto.com for a very good article on that unit.
Send me your email (macx@eoni.com) if you'd like some good
info on putting together a very stout electric AOD using mostly
factory parts from certain years/models of the 4R trans, and which one of those (totally interchangeble with an /E) that HAS all the good parts in it and that WILL bolt to w v8. About all you
need is a good quality converter (Precision @
www.converter.com, or
www.levelten.com, don't know if Lentech's converters fit a trans without their valve bodies, or Art Carr are some good ones).