looking to bite the bullet and trade the 04 3500 auto with the 5.9 in for a new 2010 with the 6.7 3.73 gears, was wondering some real world numbers people are getting for fuel mileage. old truck has 4.10 gears, looking at 2010 3500 auto with and only getting around 13mpg on hwy towing trailer and 14-15 combined city/hwy not towing. also have been reading other posts about unplugging the egr and truck still preforming regens, and getting better fuel economy. if true how easy and what is involved, any check engine light come on? do not want to make any wty troubles. thanks in advance for information i would also like to add that i also do plowing in the winter, wondering if there may be any dpf issues while plowing, from idling?

 

I have the 68RFE, 3.42's, and 265's,,,mileage is 18.25mpg on extended highway runs, about 15.5mpg average on combined city and highway driving over the course of a normal tank full.

Towing, between 9 and 11...not impressed with that, but 3.42's aren't quite optimal for towing some things. When I tow, the lightest load is 23K lbs GCVW, and goes up over 35K lbs.

Chris

 

Why not any year truck with a 6.7L engine? I do not think there would be a difference between a 2010 or 2007.5 and up for fuel mileage.
A 5.9L engine will always get better fuel mileage then a 6.7L engine.
Jim

 

I have 4000 miles on this one and I'm getting a solid 24.5 mpg city/hwy combined, and 27.3 mpg hwy. Haven't been on a cross country trip, so I think highway mpg would be higher. Should increase a little when it loosens up more.

Now for real world mpg, just subtract 10 mpg from each figure. Hehehe!

 

Mine is putrid. I get around 12 city -- 16 highway... That's hand calculated.

 

I think your last statement sums it up - subtract ten from the city/hwy and from the hwy, and that's about what I get (14 and 17). But with only 3500 miles, I know it will go up as time goes by. Heck, my Cummins ISL finally went up after 35K miles - took that long to break in. Also, I have seen my mileage higher, but it requires more attention to how I drive it than I care to pay - besides, everyone here says to drive it hard!

 

This new truck with about 10,000 miles is getting 14.5-15.5 empty mostly highway and 9 towing 13,000 lb 5er. Previous mechanically identical 2007.5 6.7L with 130,000 miles was getting 16-17 empty but still only 9-10 pulling the trailer when I sold it.

 

thanks for the info, please keep it coming. sounds like mileage might not change much for me than. definitly like all the upgrades that they did in 2010 anyone do any plowing and have any issues with dpf plugging with a 07.5-10 6.7?

 

I have about 4500 miles on my truck so far and it has the 3.73 gears. I am averaging about 17.5-18.5 mpg highway driving keeping it at around 74mph. Towing my Open Range 399BHS fifth wheel which weighs about 14000lbs cruising at around 68mph I have been getting 12mpg with most of the roads being flat with some hills driving from OH to KY. So far I am very impressed with my truck. I figure the mpgs will get better as I put more miles on this truck.

 

Truck in sig I'm averaging 13.7mpg 30% city, 70% hwy. Only 3700 miles on it so far, so i'm praying it loosens up. Once I hit 36,000 miles I know this truck will loosen up a ton!