Thank you David for the info on the oils. I was worried about the gearbox on the plus4 as soon as I realised it was the LT77 and the trouble they had with the early Discoverys. Having dug a bit deeper since your post I find that Ashcroft Transmissions and my original Morgan Handbook recommend ATF Dextron 2 or 3 for this box and MTF94 for the R380 box (Which is exactly what I have). At least I don't now feel the urgency to drain the Morgan box and refil.
