I've had a mitsu a/t foam the atf, probably, as kevin says, due to some water contamination, and the water boiled, and the tranny tried to run on foam, and of course, just whirled the converter housing without spinning the turbine, since foam doesn't have much push to it. My load may have been slightly higher, a bobcat and trailer, uphill, with two buckets. Probably 7k lbs or so.

Not responsible for advice not taken...