Goofy
Member Since: 07 Jun 2011
Location: Sunny Cheshire
Posts: 100
  
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| Idling at traffic lights in 'drive' on an automatic gear box |
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Advice please 
I'm having a debate with Mrs Goofy about sitting at traffic lights or ques or other such delays with the auto box still in 'drive'.
If I'm sitting at the lights I knock the box into neutral to save the engine / clutch strain asvthey try to drive the car forward. Mrs G doesn't and says it make no difference for a minute or two.
Can anyone shed any light on the debate please ???
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 16th Jun 2011 8:32 pm |
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DiscoDunc
Member Since: 08 May 2006
Location: Bristol
Posts: 16390
  
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there was something on here a while back were it was said the box should be left in "D" or "P", but not "N"
cant find the thread or remember why.
I leave it in "D" unless im stopped for a any length of time in which case its put into Park Duncan
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| 16th Jun 2011 9:04 pm |
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chrisc
Member Since: 18 Oct 2009
Location: Staffordshire
Posts: 362
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If I know I'm going to be at the lights for a long time I put in in N If I'm local and know the sequence of the lights and know they'll change soon I don't bother,your brake lights may even last longer ????
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| 16th Jun 2011 9:36 pm |
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VanTheNewMan
Member Since: 15 Mar 2011
Location: Not here
Posts: 206
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Goofy. I thought I was the only one who did this 
I like N at lights as it calms the engine down and feels like it rests the auto box.
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| 16th Jun 2011 10:08 pm |
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Goofy
Member Since: 07 Jun 2011
Location: Sunny Cheshire
Posts: 100
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That's why I do it. Must admit I've been driving for nearly 20 years and this is my first auto so I don't really know how to treat her.
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| 16th Jun 2011 10:20 pm |
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DiscoDad
Member Since: 06 Nov 2006
Location: Beautiful Teesdale
Posts: 3003
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Leave it in drive.
Nothing will be wearing out.
It's not like sitting there in a manual with the clutch pedal depressed and everything spinning round.
An auto box is hydraulic in action which means that it is only fluid that is circulating whilst you are sat still in 'D'.
In fact, you are probably causing more wear & tear by changing it from 'D' to 'P' or 'N' and back again!
(Engineer & 20+ years as an auto driver)
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| 16th Jun 2011 10:30 pm |
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anglefire
Member Since: 09 Mar 2010
Location: In the Club House
Posts: 4180
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You are heating the ATF by leaving it in drive - and using more fuel, if you are bothered by that sort of thing.
I doubt a minute or two would make a significant difference, but as there is no airflow across the oil cooler, it will heat up relatively quickly. Mark.
2006, D3 SE Auto - gone but not forgotten.
2014 BMW 530d M Sport Tourer.
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| 16th Jun 2011 10:55 pm |
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hughes_jh
Member Since: 09 Jan 2011
Location: Warwickshire
Posts: 294
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Am I the only one who gets a bit more "launch" when I put it into N at the lights then tip it into D and drive off?
I'm not talking F1 speeds, but its definitely quicker than if I just sit in D and then go to drive off
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| 16th Jun 2011 11:18 pm |
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DiscoDad
Member Since: 06 Nov 2006
Location: Beautiful Teesdale
Posts: 3003
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anglefire wrote:You are heating the ATF by leaving it in drive -,,,, but as there is no airflow across the oil cooler, it will heat up relatively quickly.
You are kidding me right?
Sat at the lights for a few minutes will make F-all difference to an already warmed-up Transmission (Fluid Temperature). There are coolers to take care of these things if you live in the desert!
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| 16th Jun 2011 11:31 pm |
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DiscoDad
Member Since: 06 Nov 2006
Location: Beautiful Teesdale
Posts: 3003
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hughes_jh wrote:Am I the only one who gets a bit more "launch" when I put it into N at the lights then tip it into D and drive off?
I'm not talking F1 speeds, but its definitely quicker than if I just sit in D and then go to drive off
Think about how that actually works.
Someone has programmed the gearbox software.
You put it into gear and then now what? Oh, you want to move off do you?
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| 16th Jun 2011 11:35 pm |
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Gareth
Site Moderator
Member Since: 07 Dec 2004
Location: Bramhall
Posts: 26708
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A gearbox in D whilst the vehicle is stopped will be static internally, but the torque converter will be absorbing the difference between engine speed, and gearbox input speed. In this situation there will be no wear on the gearbox, but the torque converter will get some.
In Neutral, the torque converter will have no slippage, and get zero wear, but the gearbox input shaft will be turning and will get some wear.
I think that there is F all difference between the two, the wear amounts will be negligible throughout the life of the car, and will make no impact on overall life expectancy. That's my opinion as an innocent bystander who leaves his car in D at traffic lights, and puts the park brake on
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| 16th Jun 2011 11:57 pm |
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DG
Site Moderator
Member Since: 12 Dec 2005
Location: The Gaff
Posts: 50949
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Gareth wrote: as an innocent bystander who leaves his car in D at traffic lights, and puts the park brake on
 Stone him !! .....stone him !!
( I do the same and then floor it leaving every  standing )  21 year LR veteran > D2 GS 2003 > D3 S 2006 > D3 HSE 2009 > D4 HSE 2013 > D4 HSE 2015 > D5 HSE 2018 > DS HSE R-Dynamic P300e 2021
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| 17th Jun 2011 12:16 am |
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willyj
Member Since: 19 Oct 2009
Location: In the not so wild west wales
Posts: 99
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I think that there is F all difference between the two, the wear amounts will be negligible throughout the life of the car, and will make no impact on overall life expectancy. That's my opinion as an innocent bystander who leaves his car in D at traffic lights, and puts the park brake on [/quote]
I second that! where theres a wil theres a way!
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| 17th Jun 2011 8:02 am |
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harrim51
Member Since: 29 Aug 2009
Location: Malvern
Posts: 275
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Put it in P to scare the person that has pulled up so close all they can see is your lights 
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| 17th Jun 2011 8:11 am |
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Frapp
Member Since: 19 Dec 2008
Location: Norff Zummerzet
Posts: 1653
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harrim51 wrote:Put it in P to scare the person that has pulled up so close all they can see is your lights
No, put it in R That really puts the up them Member of the carrot crank club
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| 17th Jun 2011 8:41 am |
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