DT12 vs 13 speed

Problem is everybody drives different.

Take me, no matter if I need to hurry or not I drive the speed limit.
55,65,70,75,80

Doesn't matter I'm about time management.

So my numbers will be way different than a driver who drives for economy. However that driver mpg depends on loads, terrain, weight, speed, wind, where fuel purchased, weather and other variables.

As for the 13 speed which is what I have. I believe you can only get those thru SFI on the KW and Petes.

If you're buying a truck from an outside vendor have them spec the most fuel efficient one they can and it'll probably be the auto.

An auto never misses a shift because you're tired.
Never over revs.

Get the one you want.

I'd get the Auto but in the Volvo.

 

I have a 13spd. I'm old school. I drive by a boost gage and E.G.T. gage. Both are direct reading not hooked to the ECM. Keep boost 10 psi or below and EGTs below 500'. And yes all conditions listed above do have an impact on miles per gallon.

 

You shift very rarely so the control isn't as great as you'd think.

Also you'll probably be in an auto for a year as a driver with sni so you'll have very limited experience with a 10 speed which is what sni company trucks are that aren't auto.

So with that said you'll have 0 exp with a 13 and your fuel economy would suffer.

Take your time, in the 18onths until you get to the point of buying things will change so much that today's info will be useless.

 

TennMann, where can I find one of them 14 spd and who makes 'em??

 

13 speed are more efficient than 10 speed. Less shifting, mostly requires flipping red splitter before going next gear. All depends how you drive, how the truck was speced. Having an auto would cost you problems with maintenance and computer on it since nearly a whole truck/even powertrain is hooked to computers. Can act up anytime and not being able to move.

 

If I had a w900L (my favorite truck as a example) with 550 hp cat with 13 speed, 3.08 rear axles, low pro 24.5. You can drive 70 at 1325 rpm and still get mid 6 mpg while driving 8H. Need climbing mountains go down 8L. Perfect for non aero truck without a need of auto. If a t660 but same powertrain, I would guarantee it would get 35% better with fuel mileage than W900.