I'd want to wait at least 5 years to see if the light duty diesels have any where near the reliability and durability of the diesels in the 3/4 and 1 tons. Ford has put out some dud diesels in the full size trucks, I'd not want to be their guinea pig for the light duty diesels.
Unless Ford has worked some aerodynamic magic, color me highly skeptical of a 30 mpg truck.
Dodge is seeing 28 with the Eco Diesel.
I know guys with 4bt's in old Ford's that are close to that 30 mpg's without being housed in an aluminum truck with a 10 speed trans.
The motor has been in the Range Rover for a while, but yeah, they've screwed the pooch on several diesels.
