Why would you put a
Dual-Clutch Transmission Fluid (DCT) into your Manual Transmission gearbox
@Sc0oby? , i think i remember using that oil on my Ford Focus RS even though it was a manual but that was specifically because it required the "WSS-M2C200-D2" specification ..i haven't looked but i am pretty sure Toyota would not warrant it unless i am mistaken?
Also putting slightly thicker in the Transfer and Rear , going from 75w-85 to 75w-90 isn't going to make a noticeable improvement on the protection front and you would also possibly be increasing drive train losses with the thicker oil which will shoot-up fuel consumption.
Few members on this forum have taught myself that bigger isn't always better and that there is specific reasons why OEM fluids are specifically fit for purpose.