I too had a lot of problems with the MT75 on my Plus4. It caused no end of embarrasment at traffic lights and roundabouts.
After a bit of Googling I came across "Castrol Syntrans Multivehicle 75W-90"
This meets the required Ford spec WSD-M2C200-C as specified for the MT75.
Result - smooth changes in all weathers and from startup.
