Transmission

[matrix]

Hi there,

I would like to know, whether it is better (on technical point of view) to keep the transmission in 'D' (drive) or turn to 'N' (neutral) while on the traffic light or on short stops. Thx guys

 

[Morzine]

Leave it in 'D' and reduce the risk of rolling backwards. If the stops are getting so long that you want to knock it out of drive then you may aswell turn it off and save some petrol.

 

[matrix]

Regards this matter I was awared of local master. He said, it is better to turn to N, if you want to prolong the service life of the gearbox. What extent is it true?

 

[jberks]

I've often wondered about this. I always presumed that holding it in D against the brakes for extended periods would add wear to the torque converter as the gearbox is under load and not able to transfer the energy to the road. Is this not true ? I don't know much about how autos work so any info would be helpful.

 

[bigt]

to N or not

Agree with Jberks - definitely better to put it in neutral for more than short periods at stop. Saves fuel as it takes a lot of load off the engine and will prevent torque convertor getting hot too - not to mention the strain on the gearbox brake bands.

 

[guydewdney]

a torque converter is just a bunch of vanes inside a drum - when the car is in D and stopped, there is nothing inside the gearbox moving, only the input side of the TC.

http://auto.howstuffworks.com/torque-converter.htm

If you put it into N then the TC can spin freely, and the shaft spins. When you then put it into D there is a clutch pack that has to engage the shaft, stop it (and the output side of the TC), then allow the TC to start spinning the shaft.

http://auto.howstuffworks.com/automatic-transmission.htm

So keep in D as no parts, especially the clutch pack will wear out. If it is for a long time, several minutes, then the worst thsat can happen is the oil starts getting hot.

Substitute clutch pack for brake bands for some gearboxes, but the mechanism is the same.

 

[guydewdney]

a torque converter is just a bunch of vanes inside a drum - when the car is in D and stopped, there is nothing inside the gearbox moving, only the input side of the TC.

http://auto.howstuffworks.com/torque-converter.htm

If you put it into N then the TC can spin freely, and the shaft spins. When you then put it into D there is a clutch pack that has to engage the shaft, stop it (and the output side of the TC), then allow the TC to start spinning the shaft.

http://auto.howstuffworks.com/automatic-transmission.htm

So keep in D as no parts, especially the clutch pack will wear out. If it is for a long time, several minutes, then the worst thsat can happen is the oil starts getting hot.

Substitute clutch pack for brake bands for some gearboxes, but the mechanism is the same.

 

[paulcallender]

Maybe I'm doing it wrong - if I'm at a standstill in traffic/whatever and my left foot (I mostly use my left foot for braking) starts aching, I put it from D into Park.

 

[Geoff_Slade]

Paul. Obviously everyone has their own individual style of driving but the perceived wisdom with autos is to leave your left foot on the floor and just drive with you right foot using that for accelerator and brake (as in a manual).

 

[paulcallender]

why? it makes sense to drive with both feet? Is there some kind of safety issue here?

 

[SLinKyjoe]

for what it's worth!!!

Many people who have driven manual transmisson tend to drive with the right foot and leave the left alone when driving autos. this is normally becasue either they have always been taught this by experienced others or,and this is more likley, they have decided to use the left foot for braking and forgot it isnt a clutch and then had to extract their face off the windscreen or maybe their teeth from the steering wheel rim.

aslong as you are fully aware that you are going to brake with your left foot and you dont treat the brake pedal as a clutch it will be okay. just remember to remove the right foot from the throttle pedal at the same time. It wouldn't be how you were taught by an instructor though.

 

[paulcallender]

Its strange, because I have developed this unusual technique. If I am driving relaxed, I will use my right foot for braking. If the driving is a bit quicker, then I start to use the left foot too. Often, I will use the left foot, then apply a little more brake with the right foot (so both feet are on the pedal at the same time), then if the road conditions change, revert to left foot only braking and 'shadow' the throttle ready to accelerate again.

It must be safer because I can get my feett (left, then right) onto the brake pedal quicker than right foot only. And I can also accelerate quicker after braking.

 

[500sl]

You sound like a total hazard on the road .

 

[davidsl500]

Mercedes Manual Says..

My Mercedes manual says that for brief stops eg., traffic lights leave it in Drive and for lenghty stops select Neutral.

I am not a wizard on auto boxes but when idlling surely there is still some engagement in Drive otherwise the car wouldn't creep foward?

I drive manuals and automatics and can firmly recommend right foot only in auto's. Whilst left foot braking can be quicker its too easy to forget what car i am in and stand on the brakes with my left foot trying to find the clutch I havent got........

 

[matrix]

Thank you for all your replies.
P.S I drive only on left foot on automatic transmission. while on manual transmission, the left is intended only for the clutch, and the right one both for brake and accelerator. It is safer and more comfortable style of driving than any else option.

 

[jberks]

On the left/right foot point I feel a rant coming on ... I'm not saying anyone here is guilty of this but.... many left foot brakers are evident from behind by the fact that the brake lights are permanently on, rendering them useless. I have struggled top avoid the temptation to drag a few out of their cars over the years as I get tired of guessing whether they are really braking, or just resting their foot. I know its personal preference , but apart from racing, I can't see the point of left foot braking. When braking, the one thing you do not want, is the throttle depressed. In a panic situation, this can, and especially with older drivers has been known to happen. Right foot braking ensure that this never happens. In terms of brake force applied, even Mr Burns could get a Merc to lock up with his right foot alone. Also, I would suspect that this method of driving would render the BAS system useless and in certain circumstances would cause the ABS to be less effective as the rear wheels are still under power. I guess the car is designed for right foot braking only.
Personally I can't left foot brake anyway as I grew up on manuals and can't judge the pressure well enough. I tried it once as a teenager in my dad's sclass. My mates in the back joined me in the front! Never tried it again.
Rant over...

 

[Geoff_Slade]

What have I started. But I agree I was taught to drive an auto years ago by a mate (but then waited this year until I bought one!). He wacked my left leg if I attempted to move it to the brake. The reason is as you quote anyone brought up on a manual has no sensitivity in their left foot I 've done the passenger kissing the windscreen trick in a hired auto! for what it's worth I'm a member of the Institute of Advanced Motorists. Their manual says"never use your left foot on the brake pedal". If it's good enough for them it's good enough for me