My 4/4 4 seater (2004) has the same feature (noise). I assumed it is the bearings on the lay shaft. I have used Ford F1045737 oil at around £48 for 2 litres. About 1.7 litres used in the oil change. Very smelly, smell sticks on the hands for ages.
While more noisy than the R380 box on my +8, the gear change on the MT75 seems to be much lighter, but not as good as on my Mazda 6
Mike Smith
