1997 American dream w/Allison MD3060. I have a transmission oil leak that is coming from what appears to be a pluged orifice that could be used for the dipstick if it were to be mounted on the opposite side of the transmission. The plug has a rubber seal with a metal plate above it and a 1/2 inch not protruding from the top. The oil leaks from this plug primarily when the vehicle is parked and shut off. Can anyone tell me how to stop the leak? Any ideas would be appreciated.