New Cascadia with DD 15

Outstanding fuel mileage without much effort.
I wouldn't run anything other than a Detroit.
I had a dd13 and now have a dd15.
Both reliable.
My current one I've have had approx a year and a half with no issues.

 

I’ve got a 2017 Cascadia with the DD15 engine and DT12 transmission. I’ve had my truck for exactly 2 years and put 263,736 miles on it. Engine and transmission have both performed flawlessly. Only two minor maintenance issues so far, one sensor and one software update.

Fuel economy is great, and the transmission works really well for highway runs. Don’t let the old timers tell you that it’s not a real truck if it’s not a manual, lol.

I highly recommend that engine and transmission combination.

 

It's not , lol.

 

Haha, well that didn’t take long.

I love the DT12 transmission for highway driving and traffic. I will admit though that if I was doing a lot of city driving I’d prefer a manual. The automated one isn’t as smooth and I don’t like the way it downshifts at slower speeds.

 

There’s nothing really “wrong” with them, I just think it downshifts too often when you’re braking so you don’t get the full benefit of the jake brake and I don’t like how it will downshift when making a turn. With a manual you would pick a gear, turn at the intersection, and go from there. The DT12 won’t let you do that... if you accelerate and you’re not already in the optimal gear it’ll downshift mid-turn as you’re accelerating out of the corner.

Like I said, there’s nothing really wrong with it, I just see a difference in how I would do it driving a manual.

 

Has the DD15 become more reliable than the DD13 now?

That's a big shift from Detroit, the DD13 was the mpg and durability champ before.

The integrated driveline with the EVO package will certainly get your fleet the best possible mpg.

The Cummins X15e (500hp/1850tq@1000rpm) seems to be a great efficiency choice too, combined with 2.64-2.85 rears and 13spd ultrashift or manual shift OD trans.