Tefistar -- I also have a duratec Plus4 with a L.S.D rear axle. I experienced some nasty sounds from the dif having put in the Castrol LSD syntrax oil until I put in 75ml of redline friction modifiers. I was told by Castrol that the U.K. Syntrax doesn't contain friction modifiers, only that sold I Aus does as it was made for the Dana Spicer axles for Holdens!!!!! Guess what Morgan use - yes, Dana Spiser axles.
Anyway once I put in the friction modifiers, all was well again!!
This may not apply to your oil, but just in case!!!!!
Cheers!
