What people do not realize is that YES, it DOES give much greater protection to the gears, sliders, synchros, and bearings, BUT it IS
TWICE AS THICK in viscosity as the DCT fluids, or even the various MTF-2s out there (which being GL-4 fluids, albeit very thin ones, also protect all of the above better than any DCT possibly could, synthetic or 'blend').
It would almost be like putting one of the 'thinner' 20W-50s into our sump, and I DO notice the 'balkiness' of shifting with the Gear 300 in the 'box up here in 'yankee-land' in the late fall to early spring
Being in the steamy Squidbilly country, the Gear 300
may possibly heat and mechanically shear down
a little bit in viscosity, despite it's "shear proof" bases stocks, but not very much.
The extra viscosity
could rob some tiny bit of power, which in jeff's case (and other BT/hybrid owners), with his added power, would not matter much, but to those on purely factory power, who want every little hundredth of a HP to the wheels
.
Again, Ford would have to PROVE that
ANY transaxle fluid used actually CAUSED any failures/problems in order to deny warranty claims.