Technosynthese lubricant for a better resistance at high temperature and longer life time. All mechanical transmission, synchronised or not synchronised gearboxes, gearbox/differential, transfer gearbox and hypoid differentials without limited slip system operating under shocks, heavy loads and low revolution speed or moderate loads and high revolution speed. Very high lubricating power decreases friction and wear. SAE 90 grade at hot temperature to provide outstanding oil film resistance at hot temperature and/or to reduce transmission noise. Fluid at low temperature to allow easier gear shifting when the gearbox is cold. Less effort required on the gear lever to shift the gears.