DD16 vs 6NZ

And now you'll have to go DD16 if you want over 505/1750.

My truck has 4.30 gears on 22.5 rubber with an 18 speed OD. That's what they recommended for my application. But next time I wanted go 3.91's as I'm at 1650 RPM at 60 MPH. I've been averaging between 5.3 to 5.7 MPG (2.4 with my pony in the winter, LOL.)
But I find it interesting to see that even the heavy spec tractors dealers have on the lots up here have 4.30's even with DD16 600's!!
I almost wonder if there is a reason for that? Like you said...maybe they are trying to keep the RPM up for less regen issues??

 

With the 3.91 gears you should be running 1550-1600 rpms at 65 mph. At least that what it runs in my KW with a CAT in it. I don't know the setup on the truck yet but the shop owner told me when I asked about the Detroit was that after 2013 they seemed to have gotten a lot of issues fixed. He was also telling me about a guy here locally that pulls double hopper bottoms grossing 105,500 and he was averaging 7 mpg. I do know that he has a DD16 and runs Montana.

 

I was told after my 2013, Detroit quit using air to dose the DEF system when you shut down. Now they do it the same as Cummins. And that is where all my problems came from.
The dealer and myself always though it was the DEF freezing up that was causing my derates, when all along it was the air that runs my DEF system that was freezing.

I was always a Cat guy. And I can say this Detroit almost feels like a Cat. Whereas I hate driving the ISX. It is better now after an update they did, but originally it's throttle was all over the map. You'd shift a gear, think you figured it out, then next shift it would either rev to the moon or drop like a rock depending on what that variable geometry turbo was doing to adjust the exhaust temp.

 

I ran a couple 470 Series 60's. Same thing, leaked oil like crazy but were great on fuel and pulled good as long as you kept the RPM's up. Didn't have a lot of low end torque. Had a buddy too that had a new Low Max with a 515 60 Series (2006 or 07?) and he had them regasket the whole thing under warranty and it still liked like faucet, LOL. But never died.
I also had a C13 Acert in a 2005 Paystar. It was the 470/485-1650 rating and it also pulled like crazy. Never had any trouble with it at all.

Our 2012 ISX600 in the first hundred thousand miles....2 fuel injection pumps, air compressor, 6 injectors, 2 EGR valves and coolers, DEF pump and doser, numerous NOX sensors and thermostats and housing.
And never any parts in the distribution wharehouses....always on back order.
Won't see any more in this yard. Which is a bummer because I wanted a new International HX. But they only come with Cummins or N13 Maxxforce.