Magnetic Seal/AGB

Mark,with regard to an email I sent just a moment a go with some pages of the AMM, would you explain the working principle of the magnetic seal as per the attached file. To my knowledge this type of seal should have magnetic fluid (fluid with suspended ferromagnetic particles) however I have not seen anything the fluid  regarding the fluid in the manual, so the question raised for me is that is there any type of magnetic seal without magnetic fluid?
furthermore would you mind explaining the differences of sealol seal and magnetic seal.

Sorry for lack of responses..... still having issues with system upgrade.

Mark did you get chance to look into?Are you still struggling with the upgrade.......

We're off the realm of my general knowledge.
All I know about gearbox components is that they all use spinning splined shafts with rubber seals. All of these use engine oil as lubrication.
I have never heard of magnetic seals being used anywhere. I certainly can be wrong on this answer also.