2015 F150 possible mpg improvements
 

In the early 70's I drove a ford box truck with a 2 speed rear differential. I would like to see this put into the new F150's. Best of boyh worlds. MPG's and towing capacity. What do you think.

I feel when the new 10 speed autos come out later next year or 2016 the mileage will improve more significantly. Or the laws of diminishing return could prove this wrong.

Seems to me, even with a 10 speed trans, being able to switch between a 3.15 diff and a 3.73 would be a plus. It would help ford to meet the new cafe standards. 3 or 4 mpg hwy adds up.

You realize that's how the automatic transmissions work now, right? Instead of a split diff, there's a second gear set in the trans. A "6 speed" isn't 6 separate forward gears, is a 3 speed auto in front of an overdrive unit that combines 3 gears with 2 for six total. It's a manual trans and a split axle all combined into a single unit. It's been like this since 2003 when the 5R110W came out; there are six total gear combinations but only 5 are used.

The 6R140 is a double OD not a triple. 4 forward gears with double ODs. Same with the Allison 1000 after they changed it.

The 8 and 10 speeds would be like having an old 4 speed manual and a Gear Vendors Gear splitter/OD unit all in one.