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Discussion Starter #1
I’m aware of the necessary steps for towing Subaru automatic cars. I don’t have any reason for coasting in neutral but I’ve always wondered if coasting in neutral can/will cause damage to the AWD system of a Subaru automatic?
 

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2010 2.5i Outback, 2015 2.5i Legacy w/Eyesight
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I’m aware of the necessary steps for towing Subaru automatic cars.
Just to clarify for anyone who isn't. No towing allowed, if it's automatic, then your car's being hauled away on a flatbed. Only manuals can be towed with all four wheels on the ground.

If your car is not recommended to be moving in neutral under another vehicle's power, I would say it is safe to assume that it is not recommended to be moving at a reasonable pace in neutral period.

As to what specific damage it causes to the AWD system, I am interested in the answer as well.
 

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I can't keep up with all the newer technology of the 5eat, or CVT.

But, many of the auto cars through the 90s and early 2000s would not move any transmission fluid if being towed flat. So, while there 'may' be some chance for a torque bind issue to stress parts, the WILL be a lack of lubrication to a lot of parts.
 

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That's right. The issue is lubrication. Unless the motor is running, the ATF pump isn't, and that means no ATF being pumped to the bearings and gears that might be turning (basically the back end planetary gear set, reduction gears, output shafts and related bearing etc).

With all four wheels on the ground and turning at the same speed, the AWD clutch plates are not likely to be damaged, but the related shafts, bearing etc would be turning without the required flow of ATF. Frictional wear, and heat build-up, would be the problem.

With the manual transmission, lubrication is normally provided by the gears rotating in the pool of gear oil, and that would be the same with and without the engine running. But the viscous coupler can be damaged if all four wheels aren't turning at the same speed, meaning all four down.

There should be no problem with the automatic coasting in neutral with the engine running, but there won't be any fuel saving, and there will be more brake wear because of the loss of added engine braking when in gear.
 

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There should be no problem with the automatic coasting in neutral with the engine running, but there won't be any fuel saving, and there will be more brake wear because of the loss of added engine braking when in gear.
The owner's manual says not to tow the CVT even with all 4 wheels on the ground and the engine running. This makes it seem like coasting in neutral would be a bad idea. Of course, then you have to wonder why even have a neutral gear?
 

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Coasting in neutral is against the law in some states. The car must always be in a driving gear in the event of an emergency where power must be applied to avoid an accident.
While it is illegal, it is also impossible to enforce.
FWIW, I recall some Saab models back in the day had a free-wheel device in the transmission that allowed the car to coast even while in gear.
 

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Discussion Starter #8
Good point UP, seems that I read one of the newer models has a feature that they called sail. It will allow the car to coast (momentarily out of gear) as in down hill while moving forward in drive. I can't recall though if the car was AWD. It was a fuel saving issue.
 

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While it is illegal, it is also impossible to enforce.
FWIW, I recall some Saab models back in the day had a free-wheel device in the transmission that allowed the car to coast even while in gear.
Yep, "back in the day" I owned two: a '66 Typ 96 and a '67 Typ 95, both two-strokes, although the Typ 95 wagon was oil injected, while the sedan was mixed 8 oz. oil to 8 gal. gas. These cars had a one-way clutch, allowing the car to basically overrun the engine at a given rpm if the car was going faster. A simpler car to maintain would be hard to imagine. But in Midwestern winters, it was a must to change to a thermostat that opened at a higher temperature AND completely block off the radiator with a piece of plywood. But after that- you were good to go. Started at 20 below like it was 70 above.
 

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I’m aware of the necessary steps for towing Subaru automatic cars. I don’t have any reason for coasting in neutral but I’ve always wondered if coasting in neutral can/will cause damage to the AWD system of a Subaru automatic?
At running no. At not running yes. Fuel cut off feature does not work when you do this so fuel mileage is worse not better. No reason to do this.
 

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So, on a 2014 with CVT and 2.5 with engine running is it OK or NOT OK to drift or free wheel down a gradual incline in neutral?

Another valid and related question, is it OK to tow, in neutral with all 4 wheels down if the engine is running?

This subject apparently has not been dealt with for the past couple of year, so an authoritative update would be appreciated.
 

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Hank - I suspect that due to the nature of how CVT's work its not good to be taking them out of gear per say while the car is moving at high speeds then putting them back in gear at high speed. I would expect some pretty major CVT issues doing that given CVT's do not work like old school AT's regarding their mechanics.

Makes no sense why you would want to coast in N with todays cars except that your just simply miss informed about fuel consumption in modern cars.
 

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While it is illegal, it is also impossible to enforce.
FWIW, I recall some Saab models back in the day had a free-wheel device in the transmission that allowed the car to coast even while in gear.
My 2004 dodge minivan pretty much coasted in nuetral when the gas pedal was not pressed. Had to use the brakes quite often when in stop and go traffic on the expressway. Brake pads needed to be replaced more often than I would have liked.
 

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Hank - I suspect that due to the nature of how CVT's work its not good to be taking them out of gear per say while the car is moving at high speeds then putting them back in gear at high speed. I would expect some pretty major CVT issues doing that given CVT's do not work like old school AT's regarding their mechanics.

Makes no sense why you would want to coast in N with todays cars except that your just simply miss informed about fuel consumption in modern cars.
I thought the point of putting it in neutral while coasting down a hill wasn't that it would make the fuel cut off, but that it would make the engine run in the low RPM range instead of a higher one while in-gear.

Someone told me to do this before ( ex girlfriend ) and I tried it on my 04 Outback before reading the manual--it says specifically not to do so there. Anyway, I noticed that while coasting down a hill at say 65 mph my engine would run in the 2000-2500 RPM range. If instead I put it in neutral, it would do the same speed down the hill but the engine RPM would only read about 1000 RPM.

So wouldn't it save gas by the merit that it is going the same speed, but at a significantly lower RPM? I'm actually very interested to know because I'm starting to wonder how much the RPMs really play into fuel economy.
 

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I thought the point of putting it in neutral while coasting down a hill wasn't that it would make the fuel cut off, but that it would make the engine run in the low RPM range instead of a higher one while in-gear.

Someone told me to do this before ( ex girlfriend ) and I tried it on my 04 Outback before reading the manual--it says specifically not to do so there. Anyway, I noticed that while coasting down a hill at say 65 mph my engine would run in the 2000-2500 RPM range. If instead I put it in neutral, it would do the same speed down the hill but the engine RPM would only read about 1000 RPM.

So wouldn't it save gas by the merit that it is going the same speed, but at a significantly lower RPM? I'm actually very interested to know because I'm starting to wonder how much the RPMs really play into fuel economy.
The threat to mechanical parts coasting at high speed is to the Automatic not the engine.

Coasting in gear even with the engine being driven off the drive lines to say 3500rpm does not consume more fuel your engine becomes an air pump when driven by the wheels going down hill and creates engine drag to keep speed in check.

Coasting down hill at speed in Neutral can cause all sorts of drama with the fluid being pumped through the AT to keep things at proper temps. Not to mention kicking it back into gear at speed isn't very kind to a transmission.

More like the uninformed do silly things that wreck their car then wonder why they have car issues.
 

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To elaborate on Subiesailors post and ignoring any mechanical harm,

With modern cars, they actually cut the fuel when you release the gas a high speeds, the engine is then driven by the transmission and the momentum of the car. The engine is not firing and therefore consuming no fuel, as SubieSailor said it's acting as an air pump, compressing intake and pushing it out the exhaust.

In short, coasting in N is forcing the engine to idle and use fuel when otherwise the fuel would be shut off and it would essentially be coasting.

On old cars that had no way to tell what speed it was when you let off the gas, yes it could save fuel by idling at a lower rpm vs letting the engine rev. But any modern car with an ECU is going to do better than that.
 

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Not to mention the most fuel inefficient point in the engine cycle is at idle - I've burned a half a tank of fuel idling my car in the parking lot with the AC on for two hours.
 
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