Help, leaky 727
Get the factory pan gasket from a 518 series transmission. Torque it properly and the leaking problem should disappear. This type of gasket is being used by the big 3 to prevent leaking problems (warranty). I've had a couple of late model GM vehicles with that type of gasket in it, and never a leaking problem.
I live in Langley, so send me a private message and I'll tell you where to get this type of gasket.