general Fordautomobile question...

Ford recommends that I put Automatic Transmission Fluid with MERCON III in my manual transmission... It also recommends that you use it as powersteering fluid.

ATF is a good hydraulic fluid.... that's why they use it in power steering pumps and automatic transmissions. But ATF isn't as good a lubricant as gear lube.

So... why do they recommend a lesser lubricant in manual transmissions when it doesn't need the fluid to act as a hydraulic fluid? They don't run it in differentials, and older manual transmissions ran gear lube....

Any thoughts?

-Sal