18 mpg Dodge while towing?

JIMNLIN wrote:

azdryheat wrote:
Friend claims 18 mpg while towing 35' toy hauler with 2003 Dodge Cummins Diesel with manual transmission. He says he never goes over 55 mph. Is he for real?

I have a same '03 Dodge/Cummins NV5600 305/555 HO 3.73 axle 2wd in a 2500 short bed quad cab truck.

19 mpg while towing a heavy TH ???
...could be a single best tank using the short fill method.
....... watching the fuel guage and guessing at mpgs.

A '03/'04 305/555 Cummins HO does get some of the higher mpgs. Mine has averaged 12-12.5 mpg (pencil figures) over several tanks on long trips pulling my 11000+ lb 5th wheel trailer.

My dad has an 03 Cummins and gets identical MPG towing his 14k GVWR 35 ft fifth wheel. He did say that he hand calculated 14 MPG tank one time... but that was an anomaly... he pulls around 55-60 MPH as well.

Thanks!

Jeremiah