What is the most fuel efficient diesel truck in the last 10?

Looking at getting a new used truck. Most of my driving is highway. I will pull a trailer seasonally.

I want something that is going to get good highway mileage. I would like to get over 20.

07 dodge

2001 dodge3/4 diesel 24mpg highway pulling a 31'tt 18mpg on the interstate 20mpg @55mph stock engine

Certainly not the Blue-Tec Dodges. The best mileage my 08 3/4 ton 4x4 has ever got is 15.8

Is that a 12valve or 24valve

5.9L Dodge 2wd is the best I've seen.

2001 is 24 valve

the new 6.4 is good if you do a dpf delete, other then that the old cummins or the 7.3 is awesome

I pull with Dodge 3500 4 wheel drive...5.9 Cummins..great on fuel, consistent 22/23 hwy mpg..boat is very light..18.5/19 mpg towing..dont even use the tow haul..constantly check the mirrors to make sure it is back there lol...mine is not a dually..great engines...2005 5.9 24 valve..lots of power

IMO a 2001 or 2002 Dodge 3/4 ton will get the best mileage of any diesel in the last 10 yrs. Get 2wd and manual transmission. This is a towing machine from factory too. If you are not doing any serious towing you can change the gear ratio in the rear end and get some really great hwy mileage. I think they come with 3.73 factory. I would consider 3.55 or so if not going to be hooked up to heavy loads.
There was one year of Dodge when the automatic transmission did not have overdrive, I think it was '90 or so, but the 4x4 3/4 tons had 3.08 gears. They would get some crazy hiway mileage. Something like 25mpg or so. That is pretty awsome for a 4x4.

My 2002 GMC gets 17-18mpg if I keep my foot out of it. It gets 14-15 pulling my boat now that I have it set up better. It is CC, 4x4, 2500HD. I would get better mileage without the monsterous grill guard I have on it, but I hate hitting deer.

I agree...a non 6.7 Cummins, a common rail would be the best, '03 or later. If you want good milage, get a 6 speed manual transmission and a 2wd!!

Probably any diesel that came out before the EPA started choking down the motors, would be more fuel efficient than the newer ones. I think its a usless battle between the diesel motor companies and the EPA. The EPA chokes down the diesel motors every couple of years with new emission controls so the motor manufacturers keep upping thier displacements to get the keep good power numbers.
I have read that that was pretty much the total reasoning for Cummins going from a 5.9L to the 6.7L. The EPA was going to choke down the 5.9L with new emission devices so Cummins upped the size of their motor so that their customers wouldnt see a decrease in power.

any diesel that you can put a programmer on and set it on effiecancy mode will get mid 20s mpg, then set it to performance and run with vettes no problem, not much of a fan for the newer diesels, but the 5.9 cummins, 7.3 powerstroke and the 6.6 duramax are great motors if you keep up with them. the new 6.7 cummins and 6.4 powerstroke i havent heard anything good about them yet but being faster....

The new 6.7 Ford diesel is supposedly getting 22-23 hwy mpg. Can't wait to verify that.

I 2nd that. I had a 2007 quad cab lone star edition 4x4, auto. I averaged 22mph on the hwy. 17 pulling a bobcat.