I have had good results using 1 790 199 Ford 75w-90 BO in my MT75 box in my 2011 car. You will need 2 litres as it takes about 1.3 litres to fill to filler lip.
I had quite a conversation at a Ford Transit service station. Apparently Ford are aware of the “notchyness” of that gearbox & have worked on improving the oil
