Is there something weak about the expensive 2.74 ratio gear sets from AA?

Is it true that some OD unit gear sets for Cummins diesel transmissions are straight cut teeth for less friction drag, but give off slightly more noise?

Anyone know what the frictional horsepower percent loss
for a 727, 46, 47, or 48 is?

When the Chrysler press release for the new 8 speed Torqueflte came out last year
one of the things it said was that it was
98 percent efficient in any of the 8 foward gears,
which kind of astounded me.