[buzzinhalfdozen]

I agree you must have an unintended pressure leak, 2 most likely spots are the Valve body area or the frt. pump gasket area. A full manual valve body would not cause this issue unless there were a crack or porosity, since you've changed it you can rule that out. I would do as Tom suggested and have someone familiar with these trans. look at it, may save you money in the long run. Joe