putting x5 into N at traffic lights
 

hello, good or bad for engine to keep it in neutral when stuck at lights? 3.0d auto is the vehicle if that makes a difference, thanks

nope. wastes more gas as idle rpm is slightly higer than in D.
and extra shifting is bad for the trans.

so no point in doing it

What would be the benefit of doing this? It doesn't make much logical sense to drop it into N white at a signal that is only going to take ... 30-60 seconds?

Only benefit is you don't have to hold the brake.

For reasons stated above, not smart to do it on a regular basis.

if you have foot problems and cant hold the break than pull the ebrake

It makes no difference to the internals of the transmission.

The only difference in wear is to the shift linkage.

Putting it in neutral or park also stops you or at least slows you down from taking evasive action in the event of a pending collision, so it is considered a bad practice in some jurisdictions.

I almost always put mine in neutral at a stoplight... Allows me to give my clutch leg a break! ;)

It also takes a load off the throwout bearing; the TO is spinning with the clutch disengaged.

The question was about an automatic transmission.

Agree with you that a manual transmission should be in neutral at a stoplight.

i never do it, and i know some people that put it in N to roll down at a certain speed when the same thing can be achieved while in drive..

in manual, it is the matter of fact - you can even drop it in N while coasting to the red light, stop sign, etc... if you are driving manual, that means that you are more involved with the operation of the vehicle...
in automatic, for all the above reasons, makes no sense... I totally agree with JCL on the evasive maneuvers in case of a pending collision, hostile takeover, possible carjacking... err... well, at least where i come from or go to... lol...

ok on this island apart from roads being dire,drivers being just as bad, the traffic scheduling is pants too, some sets of lights have you waiting for anything up to 2 mins !

i just thought not having the vehicle (as mentioned an auto) in D will be less stressful for engine? seems consensus is it drains more fuel than keeping it in D and there is no benefit

I always shift into neutral if idling for a while at traffic lights, does it not wear the clutch or anything if you sit in drive with the break on, because your effectively holding the car back?

Wayne

E53 3.0d Sport

It's common now for the latest designs of 6/7/8 speed autos to automatically select neutral (without you knowing it) during in-gear idle, to reduce converter drag & save fuel. Not true for the 5-speeds though, so you have to do it yourself !

http://www.fullfatrr.com/forum/post130764.html#130764

Phil

Confusing, since the new cars shut of the engine after a few seconds at a stop, I sometimes go to neutral so I don't have to hold the brake, but I did wonder about the slight "shock" of dropping it back into drive...would be nice if it didn't creep at a stop.

Something that I do when in bumper to bumper crawling traffic is that I put the transmission into steptronic, select 2nd gear, and then leave it there until the traffic opens up. I can get stuck in long queues that can take 10 - 20 minutes to clear, so I feel that sitting in 2nd is better than having the tranny shifting into 1st every time I stop, going into 2nd if I move a few feet, and then shifting back to 1st when I stop again. I have the 3.0D, and it has so much torque that idling forward in 2nd gear from a standstill in no effort at all.

Putting the tranny in N at the lights is not good practice with a BMW as it will not go into drive again without your foot being on the brake. So if you forget, and try to accelerate away when the light changes, you then have to put your foot back on the brake again to get it to go into D, whilst you are messing around doing this the guy behind you just rammed into your tail!

This also applies when free wheeling to the lights, if you are still in motion it will go back into D without you having to brake, but as soon as you almost stop, the safety feature kicks in and now you have to touch the brake pedal to get it back into D. The guy crawling along on your rear fender see the light change and expects you to take off like a normal BMW driver... but you are suddenly grabbing the brake!

When I had the 2-1 hard downshift I always switched to N and still do it sometimes due to the habit I got. If you do it everyday it becomes a habit and you don't forget to put it in D when the lights turn green (similar for manual drivers).
Now, going to 2nd from the start to avoid switching to 1st might be an option although the adaptation feature should do that for you. The driving adaptation values are changed based on the driving style, so the car shouldn't switch back and forth gears if for the last few little while it was doing that. It should keep it in one gear.

Do you save on gas going to Neutral? it sure it does but probably not a lot. Somebody mentioned earlier that the rpms go higher if you go to N. There is a setting for that. You have about 4-5 rpms settings if I remember right: idle, idle with AC on, idle in D, idle in D with AC off, idle in D with AC on... If your car goes to higher RPMS when in idle then it is set that way.
I used INPA to monitor a few values in my tranny while driving and one of the parameters was 'load'. When I had the car in N that value was low or zero. When I put it in drive with zero increazed rpms I had a load value and when I had the idle rpms set to +50 or 100 it was even a higher load which you would translate to more gas overall.

Great explanation Phil.

Doesn't putting it into neutral effectively drop line pressure on a hot running trans. Then putting it in drive raises said pressure. Phil, are you saying it is less stress and change of state on the trans than just leaving it in drive?