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2002 ML 320
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Discussion Starter #1
I have been hearing a lot about hypermiling, by trying to get more than the EPA MPG. One of the way is to coasting on neutral. If you are coasting at 55 MPH and shift it Drive on an automatic, is it okay? I have done it with manual transmission and it is no problem. But will the automatic transmission shift right away to the 4th or 5th gear?
 

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2002 ML 500, 1994 Ford Explorer donated to Doctors without Borders
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I have done this while coasting on a long down grade, but I don't know the answer to this. I can tell you that when coasting in Neutral at 65 mph and shifting to D, it goes right to 5th gear. I don't know how the transmission feels about this.
 

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99 ML430 - 13 328i
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1,112 Posts
i wouldn't do it. cars in neutral and then you are forcing the gears to lock into each other at a certain speed. i doubt its ever good
 

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2002 ML320
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1,951 Posts
I would not recommend this in an automatic... manual... ok press the clutch in while coasting... but autos... no
 

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1999 ML320
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273 Posts
I don't see it causing any harm, especially if you blip the throttle to the correct RPM and then shift into drive, so your transmission and engine are spinning at the same rate... But I'm no expert.
 

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2002 ML500 Silver
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76 Posts
while I do not coast in Neutral, I do use the shifter to slow the car down if I am flying by a radar or speed trap. The car knows what to do from gear to gear but am not sure if it does going from N to D at speed.

I would not make a habit of it. A little gas savings over several years will be gone when you have to replace the transmission because of it.
 

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99 ML430 - 13 328i
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1,112 Posts
while I do not coast in Neutral, I do use the shifter to slow the car down if I am flying by a radar or speed trap. The car knows what to do from gear to gear but am not sure if it does going from N to D at speed.

I would not make a habit of it. A little gas savings over several years will be gone when you have to replace the transmission because of it.
i agree. going from d to n and back will just end up breaking stuff
 

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Black 2005 ML 500
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1,662 Posts
On my former 2001 ML 320, whenever I got close to a light with it, and put my ML in neutral to roll to a stop (since I was used to manual transmissions and this is a common thing to do), my ML transmission will go into limp mode if I did not get to a complete stop. I would have to stop the engine and restart it for it to work again. I almost got rear ended when I did this and couldn't accelerate..

If I rolled almost to a stop, I could feel a click on the transmission shifter and then it will be fine, but if I was rolling fast in neutral and then I put it back to gear and try to go from there, my transmission will go into limp mode.

I haven't tried on my 2005 ML 500 but don't think I want to try it again.. My 2001 ML 320 did this since brand new all the way to 108,000 miles and the dealer said that there was no problems with my ML.. and the only thing that never broke or failed in that ML was the transmission.. besides of course this issue... :)


AC
 

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2007 ML 500, 2008 ML 550, 2011 ML 63 AMG
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363 Posts
The big concern I would have is the lack of lubrication.

In an automatic transmission all of the oil pressure is generated by the engine spinning the torque converter which in turn spins the pump.

The problem is that the entire gear cluster is connected to the output shaft (the same as it does in a standard transmission) regardless of anything else. If you turn the output shaft, the entire gear cluster spins, regardless of what the engine is doing.

In a normal driving situation the engine & transmission are locked together and turning at the same speed. The faster the engine goes, the faster the pump gets spun.

If however you are coasting downhill at 65mph with the transmission in neutral the entire gear cluster is spinning at highway speed, but the pump that is supposed to be providing it with lubrication is only idling along.

IMHO, it's not worth the risk, you might save $5 worth of gas at the expense of a $3,000 transmission. Doesn't seem like much of a bargain to me.
 

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ML430, V70T5
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Whatta dumb and unsafe idea. Does anyone ever look at the trip computer and the instant mileage reading when driving down a steep hill with your foot completely off the throttle?

I "coasted" downhill in DRIVE and saw 70 mpg on the trip conputer. I tried it again in NEUTRAL and saw the same 70 mpg.
 

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'03 ML350
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211 Posts
i believe there is a section in the manual that say warranty is void if you do this kind of thing. i don't know how mb will know but i remember reading it in the manual.
 

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2013 C250
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7,273 Posts
i believe there is a section in the manual that say warranty is void if you do this kind of thing. i don't know how mb will know but i remember reading it in the manual.
Really?
 

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2002 ML55 AMG, 2005 Chrysler Crossfire Coupe Limited, 1999 C280
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4,714 Posts
I don't have any technical knowledge or experience on this; but I have to say it just doesn't seem right to be doing this sort of thing in an automatic transmission - Especially in a comparatively brittle automatic transmisison like that in the ML.

Can one really save that much on mileage by doing this anyway?
 

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2006 E55: 1999 ML430; 2002 E430 4matic; 1988 190E 2.3; 1993 XL883
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i believe there is a section in the manual that say warranty is void if you do this kind of thing. i don't know how mb will know but i remember reading it in the manual.
Quoting from the manual:
Do not engage "N" while driving except to coast when the vehicle is in danger of skidding (e.g. on icy roads)

Important!
Coasting the vehicle, or driving for any other reason with sector lever in "N" can result in transmission damage that is not covered by the Mercedes-Benz Limited Warranty.

Doesn't sound like a good idea.
 

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I have been hearing a lot about hypermiling, by trying to get more than the EPA MPG. One of the way is to coasting on neutral. If you are coasting at 55 MPH and shift it Drive on an automatic, is it okay? I have done it with manual transmission and it is no problem. But will the automatic transmission shift right away to the 4th or 5th gear?
There are certainly better ways to improve fuel economy. That would not be the route I would take.

With regards to coasting in neutral and resulting damage, I have been doing this for a few decades. I also drive with one foot on the brake pedal and the other on the gas pedal. I have done this on all the automatics that I have driven. It doesn't matter whether it is a US made car, Japanese, or German, I have coasted in neutral in them. Now with many cars, it is so easy to do. Before with the column mounted shifters, it was harder to put into neutral and not accidentally put the gear into reverse. Knock on wood, but up to this point, I have never accidentally put one into reverse.

Looking back, I have never experienced a transmission problem with any of the cars that I drove.

Please note that once the transmission is out of gear, there are safety implications that the driver must understand.

The automatic transmission will engaged back at the right gear in all the vehicles that I have driven. However, at highway speeds, it is a good idea to blip the throttle to match rev's in order to get a smoother engagement.

If you go down a mountain riding on the brakes with the tranny in neutral, yours brakes can fade, unless you have those high performance braking components.

On a related note, I have heard that Taxi drivers put their auto trannies in neutral at red lights in order to prolong the life of their automatic transmissions. This makes sense since the torque converter would not get as hot, less "slipping" means less heat.

Generally, for most drivers, it is not a good idea to do this since you can get yourself getting caught in a dangerous situation, just like driving with two feet in an auto equipped car.

I find it hard to believe that any major motor vehicle manufacturer would equipped its vehicles with automatic transmissions that would do damage if their vehicles coast in neutral. That would be not make sense since coasting in neutral could be an important option the driver would want to choose to do under special circumstances from time to time. It would be appreciated if someone can provide a reliable source proving that damage would result from coasting in neutral.
 

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1999 ML320
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273 Posts
There are certainly better ways to improve fuel economy. That would not be the route I would take.

With regards to coasting in neutral and resulting damage, I have been doing this for a few decades. I also drive with one foot on the brake pedal and the other on the gas pedal. I have done this on all the automatics that I have driven. It doesn't matter whether it is a US made car, Japanese, or German, I have coasted in neutral in them. Now with many cars, it is so easy to do. Before with the column mounted shifters, it was harder to put into neutral and not accidentally put the gear into reverse. Knock on wood, but up to this point, I have never accidentally put one into reverse.

Looking back, I have never experienced a transmission problem with any of the cars that I drove.

Please note that once the transmission is out of gear, there are safety implications that the drivers must understand.

The automatic transmission will engaged back at the right gear in all the vehicles that I have driven. However, at highway speeds, it is a good idea to blip the throttle to match rev's in order to get a smoother engagement.

If you go down a mountain riding on the brakes with the tranny in neutral, yours brakes can fade, unless you have those high performance braking components.

On a related note, I have heard that Taxi drivers put their auto trannies in neutral at red lights in order to prolong the life of their automatic transmissions. This makes sense since the torque converter would not get as hot, less "slipping" means less heat.

Generally, for most drivers, it is not a good idea to do this since you can get yourself getting caught in a dangerous situation, just like driving with two feet in an auto equipped car.

I find it hard to believe that any major motor vehicle manufacturer would equipped its vehicles with automatic transmissions that would do damage if coast in neutral. That would be not make sense since coasting in neutral could be an important option the driver would want to choose to do under special circumstances from time to time. It would be appreciated if someone can provide a reliable source proving that damage would result from coasting in neutral.
Agreed
 

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05 500
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No, I don't. First off, like 350insp pointed out, the manual does say warranty voiding damage may occur and the reason for this is oil starvation like DaMurf quite well explained. Now, I don't know if this is a MB only thing. Simply because other vehicles can handle this doesn't mean it should be done with a ML. I used to do it with my Pathfinder and never had any problems for over 100K miles. However, as far as I know, all other vehicles don't have MB's so called "lifetime" tranny fluid. Is that a reason they ask not to coast in N at speed? I don't know, but I do know that coasting at highway speed in the ML may cause oil starvation to the tranny which may lead to tranny failure. Want to save on gas, "coast" in D at posted speed, accelerate smoothly from stop, slow down gently and gradually, even draft those 18-wheelers every so often if you wish. No matter what you do, you'll still be under the 25mpg mark unless you get a more fuel efficient vehicle.
 

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2007 ML 500, 2008 ML 550, 2011 ML 63 AMG
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IMHO, coasting in neutral is sort of like answering the question "Honey do these pants make my butt look fat?" in the affirmative.

We probably all know people who've done it and gotten away with it, but it's just not a wise thing to do, nor is likely going to be something that doesn't cost you dearly one day.

As I said, why risk thousands of dollars worth of tranny damage to maybe save five bucks?

There are valid, and proven technical reasons for not risking doing it.
 

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2013 C250
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7,273 Posts
For some real hyper-mileage, consider a Smart car.
 
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