[troublemaker]

A jerk is never good for any tranny. You should wait till it actually engages fully.

Also, the way to judge the health of an AT is to see how fast it engages. It should engage right away. If it takes time to engage (you can clearly feel it when you move it to D), that is not a good sign.

Originally Posted by Abes

I do slip the AT into N at signals, every time.

The only flip side I can think of is, if you are not paying attention when the signal turns green, the car behind you honks & you slip the AT into D and release the brake instantly & step on the gas, there is a 'slight' delay in the gear engaging, and the car moves forward with a jerk. I don't know how this will affect the AT.

[Guna]

Originally Posted by troublemaker

A jerk is never good for any tranny. You should wait till it actually engages fully.

Also, the way to judge the health of an AT is to see how fast it engages. It should engage right away. If it takes time to engage (you can clearly feel it when you move it to D), that is not a good sign.

Originally Posted by Abes

I do slip the AT into N at signals, every time.

The only flip side I can think of is, if you are not paying attention when the signal turns green, the car behind you honks & you slip the AT into D and release the brake instantly & step on the gas, there is a 'slight' delay in the gear engaging, and the car moves forward with a jerk. I don't know how this will affect the AT.

Jerk probably Abes is referring to is the torque multiplication that happens in ATs. From a stand still, if you try to take off in hurry, there is a always this jerk.

[Samurai]

Originally Posted by Abes

I do slip the AT into N at signals, every time.

Why do you do that? I can think of slipping to P, but why N? The only time I have ever used N is on automatic car washes where the driver is not supposed to be inside.

[jigbarai]

Originally Posted by Samurai

Why do you do that? I can think of slipping to P, but why N? The only time I have ever used N is on automatic car washes where the driver is not supposed to be inside.

Save fuel, for one !
It is the same as moving a manual tranny to N at a signal (instead of leaving it in gear with the clutch pressed).

In D, the car is doing its bit to keep moving. Which means at a signal you'd have to keep the brake pressed. Better option (if it isnt a slope) is to put it to N and relax.

[Samurai]

Does it really save fuel? You are in idle rpm whether in N or D.

Originally Posted by jigbarai

In D, the car is doing its bit to keep moving. Which means at a signal you'd have to keep the brake pressed. Better option (if it isnt a slope) is to put it to N and relax.

Well, even in N, one has to keep the brakes pressed. I generally move it to P, switch off and relax totally in long duration red signals.

[The Saint]

Either you can do in P or N, whatever you are comfortable with, though going to P everytime takes longer to come back to D. Whatever you decide you should be removing it from D if you are stand still for a long time, because if you are in D then you break pads are activated all the time which will result in faster wear and tear of the same.

[diffsoft]

Originally Posted by Samurai

Well, even in N, one has to keep the brakes pressed. I generally move it to P, switch off and relax totally in long duration red signals.

Originally Posted by The Saint

Either you can do in P or N, whatever you are comfortable with, though going to P everytime takes longer to come back to D.

I think Samurai has a point - when you keep it in P the car is locked (?) in the Park mode so even over minor unevenness of the road the car remains stationary. If you keep it in N, the wheels are disengaged from the engine and its transmission but the car is free to move over minor inclines. So you need to either engage the handbrake or keep the brakes depressed.

However to reach P from D you need to cross R - wouldn't that create a problem?

Confession: I have always been keeping it in N

Cheers,

[longhorn]

I think its okay to leave it is N as long as the road has a flat surface. You can always use the handbrake even is the surface is not flat, to keep the car stationary. This saves time when the signal goes green, as it takes lesser time to shift from N to D than from P to D. Waiting in D is a bad idea as you are putting unecessary pressure on the brakes to keep the car stand still due to the creeping feature in automatics. Moreover, for shifting from N to D you need not use the 'clutch'. Waiting in D also leads to fuel wastage, however small it may be.

[jaguar.runs]

I always keep the gear lever in "N" when standing in a signal and use the hand brake. Benefits are quick shift from "N" to "D", less brake pedal use and less brake light glare for the car behind me.

[jigbarai]

Originally Posted by Samurai

Does it really save fuel? You are in idle rpm whether in N or D.

Well, even in N, one has to keep the brakes pressed. I generally move it to P, switch off and relax totally in long duration red signals.

It does. Well, santro does not have an rpm meter else it would show up.

Basically, the way i look at it, if the car is in D - it moves automatically at like 5 kmph whereas in N it doesnt.

Meaning there would be some extra power/torque being generated in D as compared to N. You have to keep your brake pressed in D mode to keep the car from moving.
If you are on a flat even surface on 'N', you dont need to brake - the car wont move. If it is a slope, use 'P'.

Alternately, you can also hear the engine sound to figure out the difference between D & N.

This habit (of moving to N whenever appropriate) itself should contribute to significant fuel savings and better mileage, if you happen to frequently run into signals in your route.

[Guna]

Originally Posted by jigbarai

It does. Well, santro does not have an rpm meter else it would show up.

Basically, the way i look at it, if the car is in D - it moves automatically at like 5 kmph whereas in N it doesnt.

Meaning there would be some extra power/torque being generated in D as compared to N. You have to keep your brake pressed in D mode to keep the car from moving.

My ANHC AT has RPM meter and there is absolutely no change in the idling rpm weather you are on N, P or D (with feet on brake)

[Samurai]

Originally Posted by diffsoft

However to reach P from D you need to cross R - wouldn't that create a problem?

Why should it cause any problem? The brake is anyway depressed when you do that every time.

Originally Posted by jigbarai

It does. Well, santro does not have an rpm meter else it would show up.

Santro is my current AT car, but also the 5th automatic car I have owned. Frankly I have never heard of this moving to N at traffic light theory before. Can you provide an authoritative source recommending it? Let's not deal with mere opinions.

Originally Posted by jigbarai

This habit (of moving to N whenever appropriate) itself should contribute to significant fuel savings and better mileage, if you happen to frequently run into signals in your route.

That is what you are hoping. Not necessarily true.

The automatic gearbox is designed to work in D in every possible speed, whether you are stopped or moving, only exception being reverse. The frequent moving from D-N-D at every traffic light will lead to wear and tear of your auto box and nothing else. This is my understanding, but I am willing to learn if you can provide authoritative sources claiming otherwise.

[pratim]

When I bought my car, I was advised not to keep the engine running for long time while the selector is in P. I was told that it might affect the transmission system. I am following that. However, I really do not know or, I have not explored if this is true or false.

Jigbarai has a point in that, if the car is in D while waiting for a signal, the gears are engaed, so the car will have a tendency to move ahead and one has to use brakes to stop it from doing that. Of course, keeping the selector in N will save some fuel, since the effort on the part of engine to move ahead will not be there. Besides, it helps preventing faster the brake pad wear and finally, some relax on the poor leg.

Cheers
Pratim

[Samurai]

Khangs Automatic | Car Servicing | Car Diagnostic | Cars Workshop

[proton]

Stopping at lights

Manuals
Slip onto neutral, engage handbrake and keep foot hard on the brake.

This ensures that if you are rear ended, all the damage will be at the back of the car, and you reduce chances of having to engage in insurance exchanges with the car in front. Also think of the poor pedestrians who are sometimes forced to weave in between cars to cross.

Or

Switch off, engage 1st, engage clutch, engage handbrake AND keep foot hard on the brake.

Merely keeping foot hard on the brake will lead to reacting by removing foot when rear ended, in turn leading to being shunted into front car or into way of perpendicular traffic. I have seen horrendous instances in US of just this type situations!

Automatics
Slip onto neutral, engage handbrake and keep foot hard on the brake. If you wish switch off.

NEVER engage Park at the lights! More often than not one uses the box in the D or N and believe me buddy if you are not paying attention and have shifted to the P on a light, its really very possible that one shifts to R and thinks its a D and goes crashing into the rear. Its happened to many of us.

Keeping in D results in fuel wastage AND shooting forward in case of being rear ended.