Shifting into N at the lights

[SumoDog68]

Originally Posted by CoupeKing

Where are MYTHBUSTERS when you need them.

Not that it means much, but I've been in a fair share of Taxi'a and never noticed them do it.

Taxi drivers habits are something to be looked up to ? :-)

[2011G6E]

But...when you're sitting still the auto is NOT "engaged" in a gear, and is basically only pumping the fluid around...just like if you were sitting in neutral....I can't see how it would save fuel in any measurable amount.

A little like the foolish old thing of turning your car off at the lights to save fuel and then when it goes green having to use battery power, put extra wear on the starter, and extra fuel to kick the engine over. Who'd ever think that could be a good idea...

Oh wait.....

[OzJavelin]

Originally Posted by 2011G6E

But...when you're sitting still the auto is NOT "engaged" in a gear, and is basically only pumping the fluid around...just like if you were sitting in neutral....I can't see how it would save fuel in any measurable amount.

A little like the foolish old thing of turning your car off at the lights to save fuel and then when it goes green having to use battery power, put extra wear on the starter, and extra fuel to kick the engine over. Who'd ever think that could be a good idea...

Oh wait.....

I think modern versions use some trickery of stopping one of the cylinders on TDC ready for firing stroke, and restart is basically activating injector and firing the plug?

[dunga]

If its in d (stationary) the transmission is not spinning the low gear clutch pack is engaged meaning the transmission is not rotating and the torque converter is slipping. In neutral the transmission is rotating but no clutch packs are engaged meaning the torque converter is freewheeling (for want of a better word ) and all the clutch packs / bands are disengaged and no load is transmitted to the engine its not rocket science.

[commodorenutt]

Most of the stop-start ones I hear still use the starter - especially those from the VW family, and the BMW diesels seem to do it too. I crawl up a long hill every afternoon (takes 10 minutes to travel 400m) and you hear them cranking over all the time.

The length of cranking seems to be no shorter than a normal hot start, so I don't think they've come up with how to stop it on TDC yet. It would be quite difficult unless they had some from of crank brake.

In my lifetime I've only ever fired it up from TDC without the starter twice - once in a 5L commodore that was a hot start after I replaced the power steering belt that flung off (hence turning the motor by chance to a TDC spot), and the other time was in the '28 Chev. Stopped for fuel, came back out, flicked the ignition switch and it fired up without the starter. Usually the engine stops a bit before TDC as it runs out of momentum to complete the compression, so the chances of stopping it on TDC (a fraction over actually) would be lotto chances.

I had the (mis?)fortune to experience a VW Passat CC diesel in NZ earleir this year. It drove me nuts in traffic. Apparently you can disable it. That's what I'd be doing.....

[Kieron]

I had a Subaru Forester with auto stop, it starts on releasing your foot from the brake pedal, by the time you have your foot on the accelerator the engine is running. Work d well enough in pek hour traffic but I couldn stand it and turned it off. Unfortunately, you can't disable it permenantly.

I believe some systems add load via the alternator (or combination starter/alternator) to place a piston close to tdc. I'm guessing that BMW could use its valvetronic system to control piston positioning via compression.

[uniacidz]

Originally Posted by EB#

I opt for neutral (BTR 4 sp) when at traffic lights, when it looks like a longish wait. I find it's easier to just idle, with minimal pressure on the brake pedal.

I wouldn't have thought this practice would place additional wear and tear on the tranny at all - It's just part and parcel of regular driving and transmission use.

Diddo

Sent from my HTC Liberty using Tapatalk 2

[vixf6]

Originally Posted by dunga

If its in d (stationary) the transmission is not spinning the low gear clutch pack is engaged meaning the transmission is not rotating and the torque converter is slipping. In neutral the transmission is rotating but no clutch packs are engaged meaning the torque converter is freewheeling (for want of a better word ) and all the clutch packs / bands are disengaged and no load is transmitted to the engine its not rocket science.

Thanks for that, So for people who know nothing at all about transmissions, when stationary for longer periods/traffic jams etc, what causes less wear and tear on a transmission slipping it in neutral, or leaving it in d. Personally don't care about fuel consumption but care about perhaps buying a bit more life for my lovely ZF, and my Ghias BTR.
Cheers and merry Xmas

[wodahs]

Originally Posted by vixf6

when stationary for longer periods what causes less wear and tear on a transmission

don't know bout trans but when stationary youll get less wear on tyres from not doing burnouts

in the last 30 odd years ive been driving ive heard take it out of gear its safer id you get hit from behind you wont lurch forward/keep it in gear if theres an emergence or the lights change you can get out the way with out delay

take it out your putting stress on the trans leaving all trying to turn and causing friction/leave it in the placing in and out of gear is what wears the trans as it engages/disengages

I think dunga puts it well

Originally Posted by dunga

If its in d (stationary) the transmission is not spinning the low gear clutch pack is engaged meaning the transmission is not rotating and the torque converter is slipping. In neutral the transmission is rotating but no clutch packs are engaged meaning the torque converter is freewheeling (for want of a better word ) and all the clutch packs / bands are disengaged and no load is transmitted to the engine its not rocket science.

so to put bluntly when stationary in gear the only slippage is taking place in the converter (which unless they are a full lock up type , this is what they are made to do and nothing else in the trany is moving so there will be no wear in there and auto trans and converters are made with this in mind
take it out of gear the converter spins freely and the input shaft also spins but like a manual out of gear this is where all now stops hence no wear
flip a coin take your pic 50/50 half one six the other , if really concerned buy a manual
and when it comes to vehicles if there is wear your never going to remove it by doing XX your just going to move it to another point unless to remove wear you implement never starting the vehicle at all

[vztrt]

Originally Posted by vixf6

Thanks for that, So for people who know nothing at all about transmissions, when stationary for longer periods/traffic jams etc, what causes less wear and tear on a transmission slipping it in neutral, or leaving it in d. Personally don't care about fuel consumption but care about perhaps buying a bit more life for my lovely ZF, and my Ghias BTR.
Cheers and merry Xmas

Seevice it regulary and take it easy when taking off.

[pottery beige]

Originally Posted by TheInterceptor

Hi there! Every time you select d again it activates the bands in the box to select first. This will eventually lead to premature wear of the bands. So short term fuel savings but long term gearbox failure.

Not recommended!

way 2 overthinking it

every time i go out i lock my house

am i wearing ma keys/door locks out??

will i haves premature failures??

???

[BENT_8]

Originally Posted by pottery beige

way 2 overthinking it

every time i go out i lock my house

am i wearing ma keys/door locks out??

will i haves premature failures??

???

Possibly, but i'd take an entrance lock set from Bunnings over an auto rebuild/replace anyday.

I have never been one to shift to neutral at the lights, until a few weeks ago when for some unknown reason I did.
Then the lights changed and caught me unprepared, the thump that followed as I selected drive with the engine at 1200rpm when I'd realised my error and tried to correct it will remind me not to try it again...

[Optional]

You will wear your lock/key out faster the more you use it.

I guess both a key and a tranny are made to be used over and again though

[Sabantien]

Originally Posted by 2011G6E

But...when you're sitting still the auto is NOT "engaged" in a gear, and is basically only pumping the fluid around...just like if you were sitting in neutral....I can't see how it would save fuel in any measurable amount.

I'll admit I don't know much about the workings of the transmission, but the instant fuel use monitor above the speedo reports a small drop (same when turning the aircon off), and the car itself seems to sag, like it's not trying to go forward anymore, and the revs do drop a little.

It drop in fuel usage isn't massive, and quite honestly there's a bigger one turning the air con off. If you were a hyper miler it's the sort of thing that might be of interest, but I don't think too many hyper milers drive Falcons.

[The Yeti]

Originally Posted by pottery beige

way 2 overthinking it

every time i go out i lock my house

am i wearing ma keys/door locks out??

will i haves premature failures??

???

Absolutely overthinking it

But let's be honest here if you feel the "need" to select neutral at the light I think you have manual envy and perhaps should have selected "manual" when buying the car

All in all selecting N at the lights is a bit of a fapfest

[wodahs]

Originally Posted by The Yeti

Absolutely overthinking it

But let's be honest here if you feel the "need" to select neutral at the light I think you have manual envy and perhaps should have selected "manual" when buying the car

All in all selecting N at the lights is a bit of a fapfest

and lets face it if your really that ana! about saving fuel then you should have bought a manual anyway

[vztrt]

Originally Posted by wodahs

and lets face it if your really that ana! about saving fuel then you should have bought a manual anyway

6 apeed is more fuel efficient then the manual now.

[CoupeKing]

Originally Posted by SumoDog68

Taxi drivers habits are something to be looked up to ? :-)

Where did I say that?

If anyone wanted to save money on fuel it's a Taxi driver.

Their Boss probably said it saves $18.00 a year, but you will go through at least one transmission.

[madmelon]

Originally Posted by malazn mafia

How about shifting into N while going down an incline? Is this detrimental to the transmission?

This may actually cost you more fuel- over-run fuel cut may be active. When it's active, fuel consumption is literally zero, better than ~1.3L/h at idle...

[wodahs]

Originally Posted by vztrt

6 apeed is more fuel efficient then the manual now.

then why you all whinging about trying to maybe save a bees fart more ffs

[vztrt]

Originally Posted by wodahs

then why you all whinging about trying to maybe save a bees fart more ffs

Whos whinging? I couldnt care less...fuel is cheap in Australia...wouldnt be thrashing a turbo around if it wasnt.

[Itsme]

If I'm sitting in heavy traffic in hot conditions as most here would have experienced at one time or another I will throw the auto in "N" to take the load of the engine & auto itself, this was recommended to me many many moons ago in my younger days, as I'm aware of this has had no detrimental effect on any car I've owned in the last 42 years.
I've spoken to many people in the auto transmission businesses who have stated it is quite ok to do this.

[cobramania]

This doesn't apply for all auto's, but for the ZF 6HP26 which the OP should have in his Terry, it makes no difference shifting into N & should just be left in D.

This is from the ZF Functional Descriptions manual, but I've read a more in depth explanation elsewhere (unfortunately I can't remember where).

A new feature is decoupling of the transmission when the vehicle is at a standstill, that is to say instead of the engine remaining connected to the converter and the vehicle being prevented from moving by applying the brake, the converter is disconnected and only a minimum rotating load remains.
This has the effect of further reducing fuel consumption.