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Hi all, I have a SLK AMG 55 and when I am going to be stationary at a set of lights or in a jam I always put the auto box in N. I'm just wondering if this is just me or if anybody else does it? Does it help the gearboxes life span or make it worse? Your comments would be appreciated.:)
 

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I'm not sure either, it may just be a habit i've gotten into but the car seems to feel more relaxed as soon as it's slipped into N?
 

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Administrator 2009 SLK 55 AMG/Founding Member 2006
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nope. never. why add wear and tear?
 

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Hello From Weddington, NC

Drive, so you're ready to Drive on. Will not hurt a bit. The advive of adding wear is an excellent point.
 

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Premium Member 2007 SLK280
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I agree with keeping the automatic transmission in drive. Seems like putting it in neutral might be a habit carried over from driving a standard transmission.
 

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I think it is a valid point, even if only an academic one for short stops at lights. It's a trade off between:

Staying in D - Power going through the box so the torque converter has to to do some work to let you sit still, the shafts & bearings keep spinning.

Going into N - Additional work of disengaging and a bit more wear, but once disengaged there is no power going through the box or converter.

Obviously if you had a failing torque converter that was prone to overheating then you'd want to go to neutral.

My gut feel is that the disengaging and engaging when using neutral probably results in more wear and tear than sitting in drive, but improves fuel efficiency.

The dramatic increase of start-stop engines provides an argument that the
modern engineering is able to cope with the start-stop cycle while providing fuel consumption benefits. One could see the same argument applying to the gearboxes.

As for manual boxes, we have two options - either keep your foot on the clutch while waiting, or release the clutch pedal while waiting. The former results in 50% less wear on the clutch plates because they only open and close once, but it does increase the wear on the thrust bearing (the bit the separates the plates). Its also rather dangerous if your foot slips, for example if someone lightly bumps into your rear at a red light, your foot slips and you end up shooting into forwards into traffic.

Then there is the issue of long stops where a box in neutral is going to be advantageous although in those cases you'd turn the engine off. For example, I always turn my engine off when waiting at a petrol station, it seems so wasteful to have cars sitting around with the engine running. Having said that, some people seem to sit for ages with the engine running while waiting for someone to do shopping in supermarket.
 

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Having owned lots of different autos I have never put then into N when waiting at lights. It doesnt do the torque converter any harm to be on hold Thats what they are designed for. sitting with one foot on the brake and the other on the loud pedal gets you off the lights first. :burnout:
 

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For momentary stops there is no argument for placing an automatic gear box in to neutral during normal driving.
During longer stops going to neutral will reduce heat buildup; especially on hot days.
Just make sure you keep the foot of the gas prior to engaging the tranny.
There will be no additional wear and tear unless you have your foot on the gas prior to shifting in to drive.
On my Jeep I have a gage for the transmission temp (for towing purposes) and on hot days I can see the temperature going up during stop and go traffic; by keeping the engine at idle and just shifting between neutral and drive the temperature stays at near normal.
M2cw
 

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An interesting topic. In the hand book it says it is ok to leave the car in drive for "short" stops. If you are going to be stopped for a while, switch the engine off.

How do you define exactly what a "short stop" is?

I had a BMW 316i auto many moons ago, and I used to do all kinds of things like put it in neutral on long downhill runs to save fuel. I always put it in neutral if it was going to be sat at lights for more than a few seconds. I even jammed it in gear while I had some revs on the engine a few times just for a laugh. Never had a single problem with that car until near the end when it needed a new steering rack and I decided it was time for a change.
 

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My wife has a 2011 VW Sportwagan which is a double shaft with two clutches in place of torque converter. When you have the brake on and stoped it disenages both clutches so you would not have any stress on the transmission sort of like being in N. The Porsche Cayenne Turbo in fact stops the engine when stopped at lights with you foot on the brake and the engine start when you take your foot off the brake and you give it gas and just you drive away. Kind of strange as everything goes quite when you stop and than you heard the engine and the cars moves away from the light.
 

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My wife has a 2011 VW Sportwagan which is a double shaft with two clutches in place of torque converter. When you have the brake on and stoped it disenages both clutches so you would not have any stress on the transmission sort of like being in N. The Porsche Cayenne Turbo in fact stops the engine when stopped at lights with you foot on the brake and the engine start when you take your foot off the brake and you give it gas and just you drive away. Kind of strange as everything goes quite when you stop and than you heard the engine and the cars moves away from the light.
I would hate that engine stop thingy. I like to sit with my left foot on the brake with my right hovering over the gas pedal and gone as soon as the light hits green :)
 

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I dont drive an auto very often, prefer R) . But when I am stuck with an auto box I usually stay in D with the right foot on the brake for traffic lights and junctions. In traffic jams, into P and sit back and relax. Staying in D at rest uses more fuel than in P or N, you only have to listen to the engine note to hear that there is load on the engine in D.
 

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I was taught to drive in a manual car. My instructor (ex Hendon Police Academy) told me that when stopped at traffic lights I should disengage the gears and apply the handbrake. His reasoning was that, apart from wear on the clutch realease mechanism (which is minimal, he said) if rear-ended or in wet weather it is less likely that your foot could slip off the brake pedal and so you are less likely to hit the car in front.

I've always followed that advice...but to be spot-on with my getaway, I watch the traffic lights so that "their" amber and red becomes my "ready, set..." before "go". For most lights in my town, I know I have 3 secords between "their" red and "my" green, so I'm getting ready to go by applying the foot brake and slipping back into gear. When I get the green, I simultaneously release the hand brake and move my foot smartly from the foot brake to the throttle.

I was told that auto boxes did not like that treatment, so when I started to drive cars with automatic tranmissions, like many others I left the car in gear at lights holding the car on the footbrake AND handbrake.

One wet day a car coming towards me lost control and hit me HEAD ON at about 80kph/50mph. The impact was enough to push my car (a heavy Rover P6B) back about 2 meters (6 ft) and yes, the impact was such that my foot slipped off the foot brake, leaving just the hand brake on...but because the gearbox was "in gear" two months after having the car rebuilt and back on the road the gearbox failed with fractured clutches and shafts....so it could be that the box would have been ok if it had have been moved into neutral at those lights....maybe....so now even at lights a move the box into "N" and apply the handbrake once again.
 
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