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Also 700s were never ecm controlled, they were renamed 4l60e when they went electronic.
I would do it right or don't even bother hooking it up and just hook up an auxiliary cooler.
Some 700R4's did have a lock up converter (I've had two). There are some posts around here somewhere about locking it up with a switch. I did a quick search and summit has a kit to control it automatically or with manual override (switch). http://www.summitracing.com/parts/TCI-376600/