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Will shifting in to Neutral in my AT hurt the transmission?

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the guys are right about no fuel in gear but I get far more coasting distance in neutral on my manual than keeping it in gear. Yes my mileage and MID do tell me I get better mileage coasting on a manual. FWIW it's an 05 acura TL and anybody with the MID on this car will tell you it's as accurate as can be. Car can't be shifted in reverse past a certain speed there's a lockout there because 6th gear and R are right next to each other.
 
Guys don't be so hard on him.

He might actually be getting better mileage because he can coast farther in N while using very little gas. Opposed to using none, but coasting much less.
 
holden j caufield said:
the guys are right about no fuel in gear but I get far more coasting distance in neutral on my manual than keeping it in gear. Yes my mileage and MID do tell me I get better mileage coasting on a manual. FWIW it's an 05 acura TL and anybody with the MID on this car will tell you it's as accurate as can be. Car can't be shifted in reverse past a certain speed there's a lockout there because 6th gear and R are right next to each other.
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I was referring more to automatic transmission cars. I wouldn't trust that lockout bumping the shift lever into neutral with reverse just one notch away. Sounds like a dangerous and completely useless practice. If you really want better mileage, get a more efficient car.
 
Bignate603 said:
You're not getting that mileage just by popping into neutral going downhill. You can't separate the effects of shifting into neutral from all your other techniques. No one in this thread has yet said anything that shows proof that this single technique saves gas.
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Oh really? I can tell you that I've actually experimented with this for several hundred miles between neutral coasting and in gear coasting, all on the same road at the same average speed. The best I could get with in-gear coasting was 35 mpg. There is a huge difference between the two. 45+ mpg/tank on the highway is not possible on an MkV Jetta 2.5L without coasting in neutral. If actual mileage logs don't convince you nothing will.
 
JulesMaximus said:
I was referring more to automatic transmission cars. I wouldn't trust that lockout bumping the shift lever into neutral with reverse just one notch away. Sounds like a dangerous and completely useless practice. If you really want better mileage, get a more efficient car.
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I used to do that every so often when I had my automatic '96 Civic. I had no issues whatsoever with the reverse lock out for the entire 12 years I had it. Actually I still do that sometimes with my wife's 2000 Passat. No issues.
 
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jhu said:
Oh really? I can tell you that I've actually experimented with this for several hundred miles between neutral coasting and in gear coasting, all on the same road at the same average speed. The best I could get with in-gear coasting was 35 mpg. There is a huge difference between the two. 45+ mpg/tank on the highway is not possible on an MkV Jetta 2.5L without coasting in neutral. If actual mileage logs don't convince you nothing will.
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If you don't have a hard time believing coasting in neutral will give you a 10 mpg jump in mileage you don't really understand what's going on. You're saying that you burned 22% less gas over a certain distance (converted to gallons per mile to get that percentage) just due to coasting in neutral. Unless the amount of extra coasting you get from rolling in neutral is over 20% of the time while you're driving the numbers just aren't believable. Again, this isn't even coasting 20% of the time, this is coasting 20% of the time past what you could have done while in gear.

Also, coasting down hills isn't really safe. After seeing morons around here coming down from northern
AZ top 80 coasting down and then refusing to accelerate until they've coasted down to 45 (all while in the passing lane) I can tell you that they end up obstructing traffic.
 
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Proprioceptive said:
I have a 2010 Corolla, AT. I like to throw the car in to "N" when coasting because it dramatically increases my MPGs... yes, I love to hypermile. I understand that the gearbox is constantly switching between gears on an AT, but will my Neutral coasting cause any ill effects in the future?
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Switching into neutral while coasting burns more gas than when left in gear for most modern vehicles. Why? Because when in neutral, the engine burns gas to keep running. When coasting while in gear, the ECU will cut gas to the engine until the engine drops to 1000 - 1500 RPM.

edit, looks like I'm late to the party!
 
JulesMaximus said:
I'd love to see one of you neutral coasting guys accidentally shift your car into reverse at 60mph.
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I've done that a few times in my car but given the eCVT it doesn't do anything....


I coast in neutral in my car when I want a longer coast because in neutral it won't spin the regen motor so the car rolls easier...(and D or N doesn't matter it shuts off the gas engine either way)

I drive a Fusion Hybrid
 
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Bignate603 said:
If you don't have a hard time believing coasting in neutral will give you a 10 mpg jump in mileage you don't really understand what's going on. You're saying that you burned 22% less gas over a certain distance (converted to gallons per mile to get that percentage) just due to coasting in neutral. Unless the amount of extra coasting you get from rolling in neutral is over 20% of the time while you're driving the numbers just aren't believable. Again, this isn't even coasting 20% of the time, this is coasting 20% of the time past what you could have done while in gear.
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For any given average speed, my car can spend about 66% of the time coasting in neutral vs. ~40% coasting while in gear. The effects are more pronounced in lower speeds than higher speeds.
 
Shifting into neutral won't do anything, it's the shifting OUT of neutral while moving will. I'm a hypermiler too and while there are those who are willing to do this, I pretty much refuse to because there are some indications that it isn't a good idea to do at all. One example is on the Volvo S60 which earlier model year cars had a problem with their transmissions failing as early as 30K miles. The reason it turns out is that when coming to a stop light, the transmission would shift into neutral and back into gear again when taking off. This shifting into and out of neutral, which was done by the transmission's own logic ended up causing premature wear. So a recall was sent out and Volvo re-flashed all the transmission logic on all the cars so that the car wouldn't do this behavior anymore and just stay in gear. The point of this feature was to cut down on emissions and to save what bit of gas you could since spinning the engine in drive while stopped DOES use more gas than when in neutral.

I SPARINGLY shift the car into neutral and just coast but for the reason above, I really avoid doing it. Yes I am aware that you have a Toyota but nonetheless I can't advocate it even if it does save fuel due to the bigger risk of having a potentially dead transmission out of the warranty period.
 
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jhu said:
So's going over the posted speed limit.



Neutral coasting works. This is what I'm getting on an MkV Jetta with the 2.5 L gas engine. For almost any given average speed (eg 60 mph) neutral coasting will give better fuel economy than coasting in gear.

BTW, real engineers do know it works. Please read up on brake specific fuel consumption to see why it works.
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What does BSFC have to do with what we're talking about?? I'll take it you aren't a real engineer.
 
Wow, guys... didn't mean to start a pissing fight here. I never said that my switching into N used less gas, just that my MPGs increased when coasting in N. Like some guys here have said, you can coast a lot farther when in N than when you're in gear.

Really, all I wanted to know was if switching to N would hurt my transmission... but then again, I seem to see a lot of evidence both ways. Oh well. I guess I should just play it safe and stick without going into N until someone convinces me otherwise
 
You're not saving gas at all. You're just pissing off the people behind you and making them blow by you at the first opportunity, thus using more gas than you are saving.
 
exdeath said:
You're not saving gas at all. You're just pissing off the people behind you and making them blow by you at the first opportunity, thus using more gas than you are saving.
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I only coast in N when I can stay at my current or higher speed. Thus, saving gas.
 
Just let the OP leave it in neutral if he wants. Don't come crying though when your rings go bad prematurely and you start to see clouds out of your tailpipe.
 
You could always open your doors up at speed as well if you're traveling downwind to act as sails - if you're a REAL hypermiler you won't go anywhere unless it's downwind.
 
mariok2006 said:
Why would this happen?
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From my experience the fuel doesn't burn as efficiently as it would be under load so some of the gas can drip down the cylinder walls. But shit I may not know what I'm talking about. After breaking apart two babies vw engines that's what I noticed. I could be wrong. I'm sure someone like ZV would have more experience than I do.
 
Side note: Do not shift into neutral on an automatic with the engine off if you plan on coasting for any distance. You will be needing a new throw out bearing soon.
 
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