from the FWIW department:
We're equipped with the MBE4000 (DD13 equiv.) factory tuned to 450hp with a 12speed Meritor SmartShift Tranny.
Moderately loaded were 36k lbs (130g / 210g of Fuel/Water). Ive seen as high as 13mpg (mixed driving from blacksburg va to destin fla) and as low as mid 8mpg. On average (houston tx to the northern shenandoah valley) we see mid to high 9s if we hold it to 65mph or less.
More often (keeping up w/ traffic) we see high 8s to low 9s (72mph cruise w/ the occasional burst to get around traffic).
'04 Haulmark (M42386) 42', 2 slide, 10kw - Pictures
'04 F350 CrewCab Longbed 4x4, 50g aux tank & gear vendors dbl over