Oil simply can't flow up and outside the bellhousing, it's impossible.
Even if the RMS was totally RS the oil would not flow or be thrown up and outside the housing, the only hole in the bellhousing is at the bottom.
If the RMS is gone the oil would be all over the bottom of the gearbox / auto, and if manual the clutch would eventually be RS also.
May be a simple loose bolt.
the only place liquid flows up is at Luna Park and that's an optical illusion, rocker cover, as the oil is splashed off the rockers all over the inside of the covers and towards the rear just above the bellhousing.
Having had a RMS let go in the Cruiser the oil does not flow up, guaranteed.