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I was just wondering. Would it hurt the transmission in the Malibu to put it in neutral while going down a hill and then putting it back in drive while I am still moving? I ask this because at whatever speed it is going down a hill, there will usually be a 1000 RPM difference between Drive and Neutral and I could save some gas doing this. Or will doing this just wear out the valve body and solenoids?
 

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I was just wondering. Would it hurt the transmission in the Malibu to put it in neutral while going down a hill and then putting it back in drive while I am still moving? I ask this because at whatever speed it is going down a hill, there will usually be a 1000 RPM difference between Drive and Neutral and I could save some gas doing this. Or will doing this just wear out the valve body and solenoids?
As long as you keep the engine running it should be fine, just realise that you'll no longer be able to use the engine and driveline as a 'brake' and will have to resort to more pedal input, which may heat your brakes up & fade them quicker if this is a large steep hill.

Don't turn the engine off, because you need power steering & brake line vacuum to drive (so it could be quite dangerous to do so), and also most auto trans' (TF's don't mind it IIRC) will wear much quicker because the countershaft won't spin and throw oil up on the other gears to lubricate them.
 

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I would never turn the engine off. I am not that desperate yet. I am just trying to find a way to increase my mileage a bit. Now that I just go work five days a week since school is out, my mileage is suffering since it is only 4 miles away, plus sitting in traffic the whole way there. My mileage is only at 20 mpg all city when I have gotten 25 mpg before on my mixed school (10 miles away on city streets) and work trips.

So putting it back in drive while moving still won't hurt it? I guess the computer is able to match up the revs of the engine to the speed I am going without damaging anything?
 

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Wouldn't engine braking in a lower gear use less gas than keeping an idle engine alive in neutral gear?
 

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I'm not sure how true this is, but I was told that when you are going down hill the car will turn off the injectors because there is no load on the engine, and the engine is turned only by the wheels, so you are actually using no fuel doing this.
 

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In the old days of carburetors coasting would save gas to some extent but with today's engine management systems I doubt you'd see any savings, and putting the car back in gear and revving the engine back up would probably negate the small savings anyway. Planning ahead and coasting to a near stop at signals or stop signs when traffic is light, hardly using the brakes, might have some benefit though.
 

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Personally I wouldn't try it.

I've always been told that when you're driving you should either be accelerating or braking, engines weren't made to coast so they shouldn't be subjected to it.
 

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I'm not sure how true this is, but I was told that when you are going down hill the car will turn off the injectors because there is no load on the engine, and the engine is turned only by the wheels, so you are actually using no fuel doing this.
This is correct. You are actually burning more gas trying to make it idle in neutral. And add that to added wear to the tranny.

Also there is always risk of needing power NOW and when you are in neutral you have to slam it into drive and then wait for it to engage the gear, by this time you are already wrecked ;) This is why neutral coasting is illegal in most of the USA.

As well on a big hill you'll have to brake and can overheat the brakes and lose them if you aren't careful...

When you stick it in to Drive the computer isn't doing anything - the transmission is engaging and "spinning" up the engine... not really a good thing

Also for a 4 mile commute where you are stuck in traffic especially in Georgia I would consider riding a bicycle strongly, you might get there faster and have a lot of gas money left over to spend on some "real" driving out in the backroads or etc.



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It probably won't save any fuel.
How are you driving that thing anyways? I'm averaging anywhere between 29-30 MPG in mine...
He must be in heavy traffic with some stop and go. Plus, using the air conditioner will lower mileage by 2mpg in that situation.

I am in the same boat as you. Getting a minimum 29mpg up to 32mpg. It is driven 50-50 city-highway though so I would expect good mileage. I am going to start using Fuel Frog to save my MPG information. Hopefully, people see that American cars get great mileage too.;)
 

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Listen to Smaart Aas Saabr, he is 100% correct.

It's not good for the transmission and you will actually burn more fuel. If you want confirmation, google "overrun fuel cut". This refers to a strategy in the engines computer that cuts the fuel supply completely whenever you're completely off the throttle and the engine is above a certain speed (usually like 1500 rpm).
 

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He must be in heavy traffic with some stop and go. Plus, using the air conditioner will lower mileage by 2mpg in that situation.

I am in the same boat as you. Getting a minimum 29mpg up to 32mpg. It is driven 50-50 city-highway though so I would expect good mileage. I am going to start using Fuel Frog to save my MPG information. Hopefully, people see that American cars get great mileage too.;)
:yup:

Best way to save gas: cruise control. I drove for about an hour and a half from my house in southwestern Ohio near Cincinnati to Columbus, and my fuel economy increased from 29.6 MPG to 31.4 MPG.
I was averaging the EPA estimated 34 MPG for a good 4 months after we bought it.
 

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No cruise control sucks if you know how to keep the foot steady ;) Every time you go up a hill the cruise will start pushing down the pedal and on the other side will cut it... better idea to not push as hard going up (slow) and don't let go on the way down (fast).
And how many highways have massively steep hills? ;)
 

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No cruise control sucks if you know how to keep the foot steady ;) Every time you go up a hill the cruise will start pushing down the pedal and on the other side will cut it... better idea to not push as hard going up (slow) and don't let go on the way down (fast).
I use cruise control on the streets even. When I come to a hill I quickly turn off the cruise control and use my foot so that it won't kick down a gear. I don't try to keep the same speed going. I figure I will get back to speed on the other side.....
 

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A lot of them if you are doing a long distance trip... sure the maximum grade on an Interstate is xxx but that is still a goodly amount. Going through the Adirondacks or the Green Mountains the cruise is going to eat another 10%....
Not in Ohio. Everything's pretty much flat here. One section of I-75 going through Dayton (NfamousZ24 should know what I'm talking about) is completely straight and pretty flat. Everybody drives like a maniac on that stretch.
You can basically drive from Cincinnati to Columbus on I-71 using cruise control the whole way and your fuel economy won't be lowered at all.
 
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