In my late 1999 7.3 6spd powerstroke long bed ext cab, I'd never get below 18mpg city. That was ragging on it. I averaged about 20mpg city. In my 1997 cummins I got 20-22 city, 26 highway. My buddies 6.0 with a 6spd and lift and 35's gets about 20mpg city.

Cummins OWNS dmax in mileage.

My father in-laws 03 Cummins get 18-19 my cousins 02 D-max gets 18-19. There both almost identical trucks the D-max is a long crew cab long bed and the Dodge is a crew cab short bed. The biggest difference is the D-max has 100,000 more miles on it. The old 12v did better on fuel then the CR Cummins.

CR's are a little worse due to the emissions crap they put on them but with a few things their mileage goes way up. Same with the new 6.4 psd's.

And the story isn't the same for the D-max?

No I'm not denying that. ALL New motors mileage is being slammed due to the restrictions. But in my experience, best unloaded mileage is cummins. Best loaded mileage is a fight between ford and cummins. Worst loaded mileage is dmax. I've heard LOTS of dmax guys bitch that they get NOTHING for mileage when loaded, and a lot of those dmax guys complain about not enough power when towing large loads.

comparing mileage on two very different trucks is impossible. did they weigh the same. how was the driving style. manual or auto. what type of tires. any towing. what gear ratio. too many varibles i say. back to the orginial question. manual 12v cummins is best bang for your buck.

but a dmax will have a better ride and more luxiorous. and easier to tune to your liking. dmax also needs other suspension tweaks due to having a ifs. also dmaxs have great reliablity. there was a guy who just traded in a dmax with 700,000 miles with nothing more than a water pump replacemnet. check it out its in the dmax section.

I agree with most of that post. I've read on plenty of dmax forums the issues of bad injectors, overheating, poor transmissions, suspension problems, etc. Not to mention you really dont hear of that many hi-mile dmax. Granted, 700k is impressive.. but how often do you hear of that? In the cummins community, thats really nothing impressive. It happens all the time. Most dmax'ers brag about 150 and 200k miles. Cummins guys brag about 800k and a million.

The tranny and the suspension are not the engine. Bad injectors where in the first D-maxx's but there fixed now. Over heating came in the next ones but thats fixed now to. It is not that old of an engine so there is going to be problems that need fixed. The 5.9 Cummins went through the same thing. I would suspect that as time goes on you will start seeing more and more Duramax's reaching the 700k, 800k, and even 1 million mile marks.

Cummins has NEVER had bad track records in their heavy duty pickup truck segment. But a dmax is nothing other than an isuzu.. tell me why isuzu cant make a diesel motor thats finally problem-free?

No diesel is problem free if you don't believe that why do I own a service manual to a 12v Cummins? Isuzu does make a good diesel. I know there Japanese but there is a big difference between Japanese and Chinese. The 5.9 didn't go through the same crap? What about the 53 block, vp44 pump failures, fuel injection problems on the first CR, dowel pins coming out of the front cover. Would any of this keep me from owning a Cummins powered truck? Heck no. Part of what makes the 5.9 such a great engine is that they stuck with it for along time and progressively made them better.