Is coasting in neutral bad

Someone show me the law where it is illegal?

The auto companies once had a unit on their cars called a free wheeler which did the same thing.

 

Basically Mexican Overdrive as it has always been referred to for many years, before some young person gets out of warp. You know what happens to some when they just push the clutch down and let it gain speed while the engine idles down hill???? Some don't let the speed slow down far enough, and when they let the clutch out it over winds the engine, and then you have a piston and a valve trying to have a boxing match. Guess what happens then???? $$$$ gone.

 

"I got me 10 foward gears and Georgia overdrive". Dave Dudley.
Back to the original post. Lets do a risk benefit analysis.
Benefit. Slight fuel savings for short period of time in isolated occasional circumstances. Small period of time to exceed governed limits.
Risks. illegal. Chance of not engaging driveline smoothly and serious damage to all components. Possible immediate need to slow down, now with no jakes available and distracted trying to re engage while having to use only brakes.
In other words, risks outweigh the benefits, particularly with fuel at $2.25 a gallon.

 

The amount of fuel going in to the trucks engine is directly proportionate to the amount of throttle given.
So I would say coasting down a hill with no throttle would burn the same amount of fuel as going down a hill in gear with no throttle.

 

Really?Then how come computer in "my" Volvo displays 99.9 mpg when I put in Georgia overdrive?

 

Remember when you took your driving test? If you coasted more than one truck length you failed.

Auto shifts are different animals, it requires no input from the driver.

Which one do you think would be better in neutral when you blow a steer tire?

As a single truck, you do not save enough to change your life. Fleets are a different story. I could have saved money changing my lightbulbs in my house years ago. I like the light better from the old bulbs.

 

Here is what I know from a mechanic standpoint,
Coasting in neutral wont hurt anything as long as clutch is engaged. When rolling down hill and driveline over powers the engine the Injectors quit injecting fuel. If In nuetral the engine will idle-using little fuel.
Bottom line its your call and what you want to do.

 

@NorthernMechanic What might your opinion be in this situation?

 

Because your onboard computer is not not actuate when you are coasting and at idle.
Do you think less fuel is passing in to an engine at idle coasting at 80 miles an hour then a engine at idle coasting at 30 miles an hour?
The answer is no but the electronic computer will show a higher mpg on the 80 mile per hour coast than the 30 mile per hour coast.
the only way to accurately calculate your fuel mileage is to hand calculate it.
This is exactly why when you file your ifta report fuel mileage is hand calculated and not just taken off the truck mileage computer.

 

When coasting down hill in gear the injectors are still injecting idle fuel.
Just like the mechanical injected engines of years ago idle fuel is still being injected coasting in gear.