6.6 year with best fuel mileage

[sturgeon-phish]

I can only look and wish for a 6.6 and I love my 6.5, but I have a question for a friend. He is looking seriously at an '04 Dmax, and he had heard that there were years that the 6.6 had better fuel mileage. He asked me and I said I did not know but would try and find out. Did the 6.6 have years with better fuel consumption rates?
Thanks
Jim

[DmaxMaverick]

From what I've seen, the federal emissions LB7 has had the best mileage (and power upgradeability) overall. These include 2001 CA and 2001-2004 49 state. 2002 CA introduced EGR and CAT, and 2004.5 began the LLY. 2006 was the first year for the 6 speed Allison, both LLY and LBZ. LBZ is desirable for the later model, as it came with a lot of nice updates. The jury is still out on the LMM (2007.5+), but it isn't looking good for MPG.

[Kennedy]

My 2005 has produced the best results for me so far. The LBZ is pretty close as well. At it's best, my 2002 came just across 20mpg where the other two can milk out 22, and maybe 23mpg...

[Mark Rinker]

Our towing averages indicate that the LB7s get the best. Some tow tunes can improve power and even mileage over stock programming.

[sturgeon-phish]

Thanks guys. If it were a crew longbed I'd be jealous.
Jim

[Kennedy]

2 of 3 of mine are crew long. The 07 will go down the road soon and a 08 crew long will likely replace it.