Alan, I mentioned your situation to a buddy who does a ot of transmission work, and he told me that he has seen a similar case, where the transmission cooler was clogged, which caused the transmission line pressure to climb, which caused the torque convertor to move forward. He recommends checking the transmission line pressures at both the cooler lines. They should be equal, if not , you have a restriction , like a clogged cooler, pinched hose or kinked cooler line, that can cause such a condition. Something to look at.