Just took a trip from SLC Utah to Black Hills SD via Yellowstone and Cody Wy. The trip there I averaged 9-10 mpg while pulling a 30ft trailer. I had more than enough power, and averaged about 70 mph and 1900 rpm. My tires are 18X35's so they are a bit tall for the gearing. Although the speedo has been recalibrated to apprximate the actual speed, the odometer is off by about 10% as per the mile marker posts.

We drove I80 on the way home and battled both a head and cross wind - typical southern Wyoming. My rpm's were 2800+ to keep up with traffic. The only way I could get back to a decent rpm was to draft behind a semi. The mileage home stunk at 6.5-7 mpg.

My normal driving is a 80% city and my mpg is 11-12 mpg. Keep in mind these values should probable be adjusted up 10% for odomoter difference. These are all calculated by had. I keep hearing about some of these guys getting in the 18 - 20 mpg on freeway driving. I would enjoy the higher mileage, but I will settle for the increased power over my old 460.

 

Your old 460 could'nt of got any better than the 6.0 in mileage towing that big of trailer.

 

your right, to clarify any confusion in my post, my old 460 got avg 5-6 while towing and 10-11 on freeway without towing.

On the same hill, my old 460 could max do 35-40 mph vs the 6.0 liter's 60-70 mph. So yea, power is better in the 6.0 liter, but fuel economy is not stellar.

My father-in-law want's to get one because he hears about such great mileage in the diesel, I keep trying to tell him that most people are not getting his perceived 20 mpg.

 

Isn't 2800 rpms close to 100mph? Were you in tow/haul?

 

Without a trailer, 5th gear that rpm could translate to 100mph, but I was not in tow haul mode due. The tranny was shifting between 3rd and 4th depending on the road. The higher rpm were caused my inclines in the road. I could only maintain 1900-2100 rpm on the flat without wind doing 75mph.

But the bulk of the miles home was being driven at 65 mph at about 26-2800 rpm just to get throught the wind.

As far as tow/haul I have not seen much use for it in my driving unless I am descending down a grade, or if the tranny is constantly hunting for the right gear. Otherwise I will kick it down a gear and hold it until I crest the hill.

 

Want milage and noise get a Dodge.

 

bigblue, I was told that if you are towing a heavy load that you should be using tow haul mode regardless. I was told this at the dealership by the shop foreman, that the trannie knows what gear is appropriate for towing. I have towed my trailor for hundreds of miles at a time in tow haul, based on what he said. I think it may adversely affect my mileage but also think it may be easier on the transmission. BIG $$$!
You might want to check that out to see for yourself if that is the right procedure to use while towing. Let me know what you find out, Okay?
Thanks, Tim

 

Im not so sure about the new Dodges, my brother just got a new cummins and he averages 16 on the highway unloaded which is what I get with my 05 6.0 sometimes. I would be curious what he gets towing but he does not tow anything.

 

I am currently on a trip from Las Vegas to WV and pulling 11k 5th wheel started with 12k miles on my truck and currently have about 14,500. The worst mileage was going thought TX on I40 with head and cross wind of 8mpg and the best has been 11.8mpg. I have been averging aroung 10 to 11 thoughout the trip at speeds of 65-70 and it seem to be getting better.

In Virgina I drove with out the 5th wheel 90% highway and got 16.8 mpg. In Las Vegas I would never see better the 14mpg. I am thinking the truck is just breaking in that is the increase in mileage. But I will tell you this I love the way this monster pulls the 5th wheel. Hills are not a problem with power to spare.

 

This is a fact. I even use the cuise control and with T/H mode on it does a better job with the RPM then with it off. And you get the benifet of the TC when going down hills.

 

Mountain...Why did he buy a Diesel????????

 

Ok, I left Las Vegas and went to Northern NV that's 395miles to the ranch, pulling the trailer with a 7000 pound Bobcat, spare bucket and parts the load was around 9500lbs. I used 33gal uphill 90% of the trip @ 11.96mpg in T/H mode, now on the way back with empty trailer I used 22gal and got 17.95 mpg in T/H mode and I also used cruise both ways, I tried to keep the rpm's at 2100-2200 as that put the spedo around 71-73mph. Now I am going to test it in town " Vegas", just filled up 27gal of diesel @ $66.23 to fill the fheiahdjnfkkgiojhg tank... Man I love this truck, I think I heard some tire scratch at the top of Tonopah grade. LOL....

 

The two times I have towed my trailer 31 foot travel trailer at abot 10000 lbs my milage dropped from an aveage of 16mpg to about 12. I also tested my milage with no load but Predator installed in tow safe mode and found my milage dropped to 13mpg may remove the tune. all else is stock