are you certain the leak isnt from the oil pump or its sender unit?or has the shifter shaft got excessive wear at the sealing area?if its leaving a puddle at a stop light that sounds like its coming out under pressure,,the shift shaft is only splashed,another thought,how sloppy is the shaft in the case?can you wobble it up and down around any?also the outer case,if its too worn the shaft movement could stress the seal too much.