Welcome, Guest: Register On Nairaland / LOGIN! / Trending / Recent / New
Stats: 3,154,776 members, 7,824,242 topics. Date: Saturday, 11 May 2024 at 06:20 AM

Auto Transmission: P, N Or D In Traffic? - Car Talk - Nairaland

Nairaland Forum / Nairaland / General / Car Talk / Auto Transmission: P, N Or D In Traffic? (3815 Views)

Auto Transmission Failure / These Habits Will Kill Your Auto Transmission Fast Please Avoid Them. / Seen In Traffic Today. (2) (3) (4)

(1) (Reply) (Go Down)

Auto Transmission: P, N Or D In Traffic? by Kashif(m): 11:55am On May 17, 2015
I don't know if this has been discussed before, but I believe we all can do it again and learn.

There has been debates on where to leave the auto transmission while in traffic, or red light. I was of the opinion that it should be left in D, as user manuals (ones I have seen) do not say otherwise. I have also heard auto mechanics (some, 'experts') say it is best left there, as that is the way auto transmissions were designed to run. Somehow, this lays credence to the 'leave it in D' divide.

However, I have been exposed to better understanding of how the most complex part of our automobiles works.

The torque converter (TC) contains the highest atf volume of all moving parts in the transmission, and is what actually 'connects' the engine to the transmission. The TC has three vital components involved in the fluid coupling - Impeller, stator and turbine. Impeller drives the turbine, helped by stator. When in Neutral (N) or Park (P), no holding element is engaged in the transmission so, all the components of the torque converter are spinning freely. In this state, the transmission is generating the least heat.

The moment you select D, and the wheels are held, the turbine stops rotating. This is when the TC starts increasing it's heat generation, as the oil that was freely flowing between the impeller and turbine is now passing over stationary turbine. The stator may also be contributing to increased heat. We know that heat is a major killer of auto transmissions.

You also lose some fuel as the engine sees that engagement as load, and tries to compensate.

These days, some new and complex auto transmissions like the ZFs automatically select neutral at idle, irrespective of what the driver selected, and reverts to first at trottle input. Fords with the double clutch requires you to go neutral at stop, to prevent overheating.

I believe it is better not to stay in D in heavy traffics. Now, is P better than N? In traffic, you see cars in front flashing their reverse lights at go, meaning they switched to P at stop. Well, if you are on a flat road, and lazy to keep your foot on the brakes, use P. If you are on an incline, avoid P, as the parking gear (and pawl) will carry the weight of the vehicle, and will gradually wear on frequent disengagement. If you must, use your parking brake first.

My personal verdict is to use N instead. It is closer to D than P (you avoid passing through R). It comes with less wear in the transmission. In all, always remember to use your parking brake!

Enjoy your Sunday.

3 Likes

Re: Auto Transmission: P, N Or D In Traffic? by DECOtech(m): 12:24pm On May 17, 2015
Nice one
Re: Auto Transmission: P, N Or D In Traffic? by Stylz69(m): 3:06pm On May 17, 2015
Very good advice. I go to Neutral at traffic lights and pull my hand brake. I don't know how true it is but I read that leaving your foot on the brake too long especially when they are hot heats up the rotors and could warp them. Whether this is true or not, I just go to N and pull my hand brake.
Re: Auto Transmission: P, N Or D In Traffic? by Kashif(m): 8:09pm On May 17, 2015
Stylz69:
Very good advice. I go to Neutral at traffic lights and pull my hand brake. I don't know how true it is but I read that leaving your foot on the brake too long especially when they are hot heats up the rotors and could warp them. Whether this is true or not, I just go to N and pull my hand brake.

You only overheat your rotor on extended brake application while the vehicle is moving, like during a descent running into hundreds of metres. If the car is stationary, no friction.

1 Like

Re: Auto Transmission: P, N Or D In Traffic? by casid: 9:24am On Jan 21, 2016
Hello Kashif,
I have a gear problem with my Honda accord. All measures have been tried and to solutions but I have made up my mind to buy another gear. I need your brotherly advice on what to look at for before buying it because our people are funny when it comes to matters like this. They claim to sell a tokunbo gear but sometime it is a repaired one. Kindly advice on the gear oil to buy, if it requires scanning after/before and other things to watch out for.

Again, lights like ABS, SRS and Engine check displays and the mechanic said if I change the gear box, they will all disappear.

Thanks for your help and other suggestion is welcome.
Re: Auto Transmission: P, N Or D In Traffic? by Readonee35L(m): 1:51pm On Jan 21, 2016
casid:
Hello Kashif,
I have a gear problem with my Honda accord. All measures have been tried and to solutions but I have made up my mind to buy another gear. I need your brotherly advice on what to look at for before buying it because our people are funny when it comes to matters like this. They claim to sell a tokunbo gear but sometime it is a repaired one. Kindly advice on the gear oil to buy, if it requires scanning after/before and other things to watch out for.

Again, lights like ABS, SRS and Engine check displays and the mechanic said if I change the gear box, they will all disappear.

Thanks for your help and other suggestion is welcome.
Change That Mechanic

5 Likes

Re: Auto Transmission: P, N Or D In Traffic? by akanniade10(m): 1:59pm On Jan 21, 2016
When in traffic or red light, my car vibrates heavily (including the steering) on D but when in N it's normal...

Vibration is excessive when Ac is on.... But once I start moving again, errthing seems fine. Car is OROBO Camry..

What could be causing this?
Re: Auto Transmission: P, N Or D In Traffic? by casid: 2:17pm On Jan 21, 2016
Readonee35L:

Change That Mechanic

Thanks Boss... I have that in mind though. But advice what gear oil should I buy when I change the gear.
Re: Auto Transmission: P, N Or D In Traffic? by Nobody: 3:34pm On Jan 21, 2016
Kashif:


You only overheat your rotor on extended brake application while the vehicle is moving, like during a descent running into hundreds of metres. If the car is stationary, no friction.

Not strictly true.

If you keep your foot on the brake pedal on heated rotors (after heavy use), the pad contact areas will cool at a different rate to the rest of the rotor. This is what causes them to warp.

In summary, the differences in heat dissipation at different points on the rotor's surfaces causes warping. Driving the car hard, and braking often WILL get the rotors hot, BUT as long as the pads are not clamped in the same spot for prolonged periods, cooling will be uniform.

3 Likes 2 Shares

Re: Auto Transmission: P, N Or D In Traffic? by msogunro: 3:36pm On Jan 21, 2016
Leave your car in drive. You're adding extra, unnecessary stress to the transmission by shifting in and out of gears. When in drive at a stop, notice that the RPM is nearly the same as when it is in park.

In addition to the additional stress, it's also for safety purposes. What if you need to quickly move to avoid danger? Your spending a few extra seconds to switch to drive.

Do your transmission a favor and leave it in drive. Unnecessary shifting is bad.
Re: Auto Transmission: P, N Or D In Traffic? by Nobody: 3:36pm On Jan 21, 2016
casid:


Thanks Boss... I have that in mind though. But advice what gear oil should I buy when I change the gear.

Buy the oil specified for your car by the manufacturer. All you need to know is covered in your Owner's Manual.
Re: Auto Transmission: P, N Or D In Traffic? by casid: 5:48pm On Jan 21, 2016
Siena:


Buy the oil specified for your car by the manufacturer. All you need to know is covered in your Owner's Manual.

Tru Value Tru Value Multi-Purpose ATF - Dexron III/Mercon.. I saw this on Jumia. Can I use this for Honda Accord 1999 4clyd for my gear oil?
Re: Auto Transmission: P, N Or D In Traffic? by Nobody: 8:33pm On Jan 21, 2016
casid:


Tru Value Tru Value Multi-Purpose ATF - Dexron III/Mercon.. I saw this on Jumia. Can I use this for Honda Accord 1999 4clyd for my gear oil?

Is this the ATF that Honda recommends for your car?
Re: Auto Transmission: P, N Or D In Traffic? by casid: 10:38pm On Jan 21, 2016
Siena:


Is this the ATF that Honda recommends for your car?

The actual has been discontinued but after thorough comments here on NL, people use oandodexron iii or ATF DW Z1 or so.. The latter is 4k for a litre which I can't afford... Meanwhile I am not ready to use abro anymore and that's why I want to seek people's opinion.. I am about to buy a new transmission this weekend and I want to ensure I do the right thing so I won't have to change again.

I open to other suggestions..

Thanks
Re: Auto Transmission: P, N Or D In Traffic? by bettercreature(m): 12:31pm On Jan 22, 2016
msogunro:
Leave your car in drive. You're adding extra, unnecessary stress to the transmission by shifting in and out of gears. When in drive at a stop, notice that the RPM is nearly the same as when it is in park.

In addition to the additional stress, it's also for safety purposes. What if you need to quickly move to avoid danger? Your spending a few extra seconds to switch to drive.

Do your transmission a favor and leave it in drive. Unnecessary shifting is bad.
Hello,this is bettercreature,kindly check your e-mail
Re: Auto Transmission: P, N Or D In Traffic? by Nobody: 12:58pm On Jan 22, 2016
akanniade10:
When in traffic or red light, my car vibrates heavily (including the steering) on D but when in N it's normal...

Vibration is excessive when Ac is on.... But once I start moving again, errthing seems fine. Car is OROBO Camry..

What could be causing this?
Your Idle Speed Controller is not working well most likely due to dirt build-up. You should start by having it cleaned. It is commonly called actuator by mechanics.

You also should have opened a new thread so as not to derail this.

1 Like

Re: Auto Transmission: P, N Or D In Traffic? by ba7man(m): 1:48pm On Jan 22, 2016
msogunro:
Leave your car in drive. You're adding extra, unnecessary stress to the transmission by shifting in and out of gears. When in drive at a stop, notice that the RPM is nearly the same as when it is in park.

In addition to the additional stress, it's also for safety purposes. What if you need to quickly move to avoid danger? Your spending a few extra seconds to switch to drive.

Do your transmission a favor and leave it in drive. Unnecessary shifting is bad.
Dont give advice that will ruin people's cars. angry

@op. Leave it in N. There's a good reason why it's located between R and D.

2 Likes

Re: Auto Transmission: P, N Or D In Traffic? by msogunro: 1:09am On Jan 23, 2016
ba7man:
Dont give advice that will ruin people's cars. angry

@op. Leave it in N. There's a good reason why it's located between R and D.

Neutral is between R and D to disengage before going to park. Its not there for any other reason.

If you can tell me why you believe it's between R and D, I will appreciate it.
Re: Auto Transmission: P, N Or D In Traffic? by msogunro: 1:10am On Jan 23, 2016
bettercreature:
Hello,this is bettercreature,kindly check your e-mail

Email replied. Thank you.
Re: Auto Transmission: P, N Or D In Traffic? by ba7man(m): 3:37pm On Jan 23, 2016
msogunro:


Neutral is between R and D to disengage before going to park. Its not there for any other reason.

If you can tell me why you believe it's between R and D, I will appreciate it.
Neutral is located between R and D so that the gear can be easily disengaged from either state with your foot on the brakes.

If it truly is to disengage before park, then it engages back again in R before P.

4 Likes

Re: Auto Transmission: P, N Or D In Traffic? by carblognaija: 8:36am On Jan 24, 2016
casid:


The actual has been discontinued but after thorough comments here on NL, people use oandodexron iii or ATF DW Z1 or so.. The latter is 4k for a litre which I can't afford... Meanwhile I am not ready to use abro anymore and that's why I want to seek people's opinion.. I am about to buy a new transmission this weekend and I want to ensure I do the right thing so I won't have to change again.

I open to other suggestions..

Thanks

Bros! Transmission oil is not what you change everyday or month. Do yourself a favor and buy the transmission oil recommended for your car or anyone of good quality. If you continue to say that you cannot afford a better oil and use what is not good, then be ready to be affording a new gear all the time. The transmission oil of one of my cars costs me 11k. Its not about being rich or affording it. It is about doing what is best for your car. If I can't afford it, I will better drop the car and buy a bicycle and have my peace of mind.

1 Like 1 Share

Re: Auto Transmission: P, N Or D In Traffic? by Kashif(m): 11:35am On Jan 25, 2016
casid:
Hello Kashif,
I have a gear problem with my Honda accord. All measures have been tried and to solutions but I have made up my mind to buy another gear. I need your brotherly advice on what to look at for before buying it because our people are funny when it comes to matters like this. They claim to sell a tokunbo gear but sometime it is a repaired one. Kindly advice on the gear oil to buy, if it requires scanning after/before and other things to watch out for.

Again, lights like ABS, SRS and Engine check displays and the mechanic said if I change the gear box, they will all disappear.

Thanks for your help and other suggestion is welcome.

You did not not state the car model. The emboldened above has more tendency to be opposite - fixing those errors may correct your transmission issue, and not the other way round.

1 Like

Re: Auto Transmission: P, N Or D In Traffic? by Kashif(m): 11:36am On Jan 25, 2016
Siena:


Not strictly true.

If you keep your foot on the brake pedal on heated rotors (after heavy use), the pad contact areas will cool at a different rate to the rest of the rotor. This is what causes them to warp.

In summary, the differences in heat dissipation at different points on the rotor's surfaces causes warping. Driving the car hard, and braking often WILL get the rotors hot, BUT as long as the pads are not clamped in the same spot for prolonged periods, cooling will be uniform.

I agree with this.
Re: Auto Transmission: P, N Or D In Traffic? by GAZZUZZ(m): 12:17pm On Jan 25, 2016
Siena:


Not strictly true.

If you keep your foot on the brake pedal on heated rotors (after heavy use), the pad contact areas will cool at a different rate to the rest of the rotor. This is what causes them to warp.

In summary, the differences in heat dissipation at different points on the rotor's surfaces causes warping. Driving the car hard, and braking often WILL get the rotors hot, BUT as long as the pads are not clamped in the same spot for prolonged periods, cooling will be uniform.

I have learnt somthing new.
Re: Auto Transmission: P, N Or D In Traffic? by 9icetoo(m): 7:49pm On Jan 25, 2016
msogunro:
Leave your car in drive. You're adding extra, unnecessary stress to the transmission by shifting in and out of gears. When in drive at a stop, notice that the RPM is nearly the same as when it is in park.

In addition to the additional stress, it's also for safety purposes. What if you need to quickly move to avoid danger? Your spending a few extra seconds to switch to drive.

Do your transmission a favor and leave it in drive. Unnecessary shifting is bad.
please do not post wrong advice here. leaving a conventional auto transmission engaged puts load on the engine and transmission. in traffic, if you are going to be at point for a long time, shift to park or neutral and engage your parking brake. this puts less load on your engine and saves you some fuel. it also prevents trans overheat. if you have an elm Bluetooth scanner, check your engine load and fuel consumption with your transmission engaged while idling and check same with your transmission in neutral. then come back and correct your post. some new ford cars will even warn you to put your transmission in neutral in heavy traffic to avoid overheating the transmission.

2 Likes

Re: Auto Transmission: P, N Or D In Traffic? by msogunro: 8:08pm On Jan 25, 2016
9icetoo:

please do not post wrong advice here. leaving a conventional auto transmission engaged puts load on the engine and transmission. in traffic, if you are going to be at point for a long time, shift to park or neutral and engage your parking brake. this puts less load on your engine and saves you some fuel. it also prevents trans overheat. if you have an elm Bluetooth scanner, check your engine load and fuel consumption with your transmission engaged while idling and check same with your transmission in neutral. then come back and correct your post. some new ford cars will even warn you to put your transmission in neutral in heavy traffic to avoid overheating the transmission.


Leaving your car in drive while in traffic puts load on the engine and transmission? Do you understand what you're saying? That's like saying a person that runs track and field experiences load when he's not running. Hahaha!!!!

I want to post an article, but last time I did so I wasn't able to post on Nairaland for several days.

Go on google and search for "Common Myths Among Young Drivers" and look at myth #5. The article will be found on Cars dot com.

If you believe Cars dot com is a trusted resource, reading the article should end this discussion.

1 Like

Re: Auto Transmission: P, N Or D In Traffic? by 9icetoo(m): 8:57am On Jan 26, 2016
Please see the link below from how stuff works.
http://money.howstuffworks.com/personal-finance/budgeting/how-to-drive-economically8.htm
it is also always good to verify whatever you read from the internet. I asked you to use a Bluetooth scanner to check your engine load when idling in traffic with your transmission in drive and check same load again when idling in traffic with your transmission in Neutral or park. If you r are in PH, I will drive over to wherever you are and do this for you if you don't mind.
When an automatic transmission is in Drive and the car is at a stop, the torque converter allows the transmission to slip so that the engine does not stall. This slipping is akin to riding on your clutch in a manual car when on a slope. In a manual car after some time, you will perceive your clutch being burnt. Same thing is happening to your auto transmission only that it's the fluid that is being burnt up in this case. The fluid can withstand a high degree of heat but over time it eventually gets burnt ( hope you get the picture?). Because the transmission is slipping but not disengaged, some load is still transmitted to the flywheel and therefore to the engine. More load equals more fuel. I hope you got the picture now.
If you are going to be at a stand still for a long time in traffic, put your transmission in N or P, engage your parking brake and relax your leg while you wait. It does a lot of good to your pocket, the environment, your engine and your transmission.

Note: I said this applies to Conventional Auto transmissions. Some modern Auto transmissions disengage the transmission from the engine when it is at a stand still and idle for a certain time only to reengage it once you step on the throttle.

1 Like

Re: Auto Transmission: P, N Or D In Traffic? by Kashif(m): 4:02pm On Jan 26, 2016
msogunro:



Leaving your car in drive while in traffic puts load on the engine and transmission? Do you understand what you're saying? That's like saying a person that runs track and field experiences load when he's not running. Hahaha!!!!

I want to post an article, but last time I did so I wasn't able to post on Nairaland for several days.

Go on google and search for "Common Myths Among Young Drivers" and look at myth #5. The article will be found on Cars dot com.

If you believe Cars dot com is a trusted resource, reading the article should end this discussion.


I am not telling you what I read off the internet. With due respect, I definitely understand how the transmission works more than you do, so I know what am saying. I have read a lot of misinformation from many internet gurus, and your quote is not different. They way you drive your car is ultimately up to you.

9icetoo:
Please see the link below from how stuff works.
http://money.howstuffworks.com/personal-finance/budgeting/how-to-drive-economically8.htm
it is also always good to verify whatever you read from the internet. I asked you to use a Bluetooth scanner to check your engine load when idling in traffic with your transmission in drive and check same load again when idling in traffic with your transmission in Neutral or park. If you r are in PH, I will drive over to wherever you are and do this for you if you don't mind.
When an automatic transmission is in Drive and the car is at a stop, the torque converter allows the transmission to slip so that the engine does not stall. This slipping is akin to riding on your clutch in a manual car when on a slope. In a manual car after some time, you will perceive your clutch being burnt. Same thing is happening to your auto transmission only that it's the fluid that is being burnt up in this case. The fluid can withstand a high degree of heat but over time it eventually gets burnt ( hope you get the picture?). Because the transmission is slipping but not disengaged, some load is still transmitted to the flywheel and therefore to the engine. More load equals more fuel. I hope you got the picture now.
If you are going to be at a stand still for a long time in traffic, put your transmission in N or P, engage your parking brake and relax your leg while you wait. It does a lot of good to your pocket, the environment, your engine and your transmission.
Note: I said this applies to Conventional Auto transmissions. Some modern Auto transmissions disengage the transmission from the engine when it is at a stand still and idle for a certain time only to reengage it once you step on the throttle.

The heat generated by the TC will not burn your fluid unless your cooling system is defective. The components to bear the brunt are the seals. It is also possible for some valves to stick to very low tolerant bores. All the same, its better to be in neutral at an extended stop.

The fuel consumption definitely higher in D, as the ECU would supply more fuel to maintain the set RPM.
Re: Auto Transmission: P, N Or D In Traffic? by 9icetoo(m): 7:18pm On Jan 26, 2016
Kashif:



The heat generated by the TC will not burn your fluid unless your cooling system is defective. The components to bear the brunt are the seals. It is also possible for some valves to stick to very low tolerant bores. All the same, its better to be in neutral at an extended stop.

The fuel consumption definitely higher in D, as the ECU would supply more fuel to maintain the set RPM.
the heat generated will not burn the fluid instantly. its the heat cycling which happens over time that degrades the fluid. the fluid eventually fails and leaves the owner with a dead transmission. that's a key reason why a lot of transmissions fail in Nigeria where they are used in *extreme* conditions.
Re: Auto Transmission: P, N Or D In Traffic? by des4ella(m): 11:28am On Feb 22, 2016
Readonee35L:

Change That Mechanic
Serious change for dat quack mechanic..

(1) (Reply)

BMW issues: (COJA) / A Clean Tokunbo Toyota Corolla For Sale / 2012 Toyota Highlander Or Lexus 350

(Go Up)

Sections: politics (1) business autos (1) jobs (1) career education (1) romance computers phones travel sports fashion health
religion celebs tv-movies music-radio literature webmasters programming techmarket

Links: (1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

Nairaland - Copyright © 2005 - 2024 Oluwaseun Osewa. All rights reserved. See How To Advertise. 83
Disclaimer: Every Nairaland member is solely responsible for anything that he/she posts or uploads on Nairaland.