Is coasting in neutral bad

You must remain in control of the vehicle at all times... If you cannot accelerate your not in Control... If your coasting I neutral your out of control... I gotta run so research out of control in neutral you will find the answers legally

 

No.

 

I am in a '17 Cascadia with the auto, and it coasts pretty often.
I can take it out of coast mode if I blip the throttle or brake.
Often as I crest a hill it will go into coast mode just before I crest the top and just float over the top until it builds up enough speed to get back in gear.
I can also get it back in gear by bumping the cruise down a few mph.

I think it is great.
There is no lack of control when the automatic is doing the 'thinking', and the shifts are always butter smooth.

Another nice thing about the auto is how it treats downgrades.
It got me really nervous at first, until I got used to it.
I've been taught to keep the rpm around 1500-1700 when going down a hill. If I pick up too much speed I would slow down enough to grab the next lower gear, and see if I could hold it at the best rpm. If not, slow and downshift again until I could.

With the auto it is totally different.
I set a speed, say 58 mph. The truck will do what it can to keep me at 64.
And it will bump it down from 12th to 11th, or 10th if necessary to do it.
Bumping down to 10th will put the rpm at around 2200. But it will hold me at the correct speed even if I am very heavy. There haven't been very many hills that I need to use the brakes on, even fully loaded.
And it dynamically controls the level of engine braking in the process.

With the DD15/DT12 combo I am not limited to a certain speed that is determined by what gear I'm in.
I set the speed I want and the transmission/engine/computer will maintain that speed.

 

That doesn't make a lot of sense. Are you saying the engine turns itself off going down hill in gear? Because that's the only way it would send 0 fuel.


Ed

 

This used to be true, but in the quest for MPG, the electronic engines (gas & diesel) shut off the fuel when in overrun conditions (driveline powering engine.) Same when on the jakes. The old mechanical engines had no way of detecting when the truck was in overrun, and thus could only drop the fuel to idle levels.

 

But if the clutch is disengaged how is the driveline powering the engine?


Ed

 

If the clutch disengages, the ECM immediately senses the rpm drop and adds fuel to catch the rpm at idle.

 

Right...so using fuel.

That's the point. If you're coasting in neutral you are still using fuel.

If you are coasting in gear, than I can see your point. Fuel not needed and drive line keeps engine turning, creating power etc.

Ed

 

from a practical stand point this does not prove to be true from what I have seen.
I have tried driving with my scanner hooked up and looking at injector pulse width modulation at coast and at idle the percentages are exactly the same.
If you have pulse width modulation then the injector is being fired.
So this is not to say that some sophisticated systems don't have this strategy programmed in them it's just not my practical experience that I have seem in the repair industry.

 

http://www.otterytransportation.com/wp-content/uploads/2016/03/Coasting-Out-of-Gear-Article.pdf