"D" or "N" when stopped?

[sowlerthjh]

I have a 1990 W124 300D auto.

When stopped in traffic, should one stay in "D" with the normal brake applied, or should one change to "N" and apply the park brake?

Thanks

 

[Lacy]

Much depends on how long you anticipate being stopped for.

I will leave in 'D' and use foot brake if stopped for a short period (like 10 seconds or so) if it's likely to be any longer than that I will slip it into 'N' or 'P' and put the parking brake on.

Whatever you do, don't use the parking brake with the lever still in 'D'. It always seems like tempting fate to me, but I know plenty of people that do it!

 

[paulcallender]

"D" and while we're at it, make sure you're using your left foot on the brake. Top tip: if you want a 1st gear start, slip it from D to 2, then back to D.

 

[nicky]

I allways leave it in drive as the car will just sit there ready to go when the lights change..

 

[Lacy]

I allways leave it in drive as the car will just sit there ready to go when the lights change..

But if it's for any length of time the driver behind you will soon get pi**ed off being blinded by your brake lights.....especially in the rain at night!

 

[turnipsock]

I always put it in N if I'm not first in line. It's pointless letting the thing fight against the brakes, it's just wearing out the clutches.

I would forget playing with the parking brake though, I use mine once a year at the MOT station.

 

[tom7035]

What if you happen to be clobbered from behind when not using the parking brake? You end up with BOTH ends squashed, plus involving the poor unfortunate in front of YOU. I'd rather use the parking brake if not in front of the queue, also eliminating the situation already raised re. blinding with brake lights on a dark wet night.

 

[jberks]

Well, I leave it in D. Unless I am going to stopped for a long time, say over a minute, in which case I may switch to N or P, but more to give my right foot a rest than anything else. I understood that the torque converter took all the slip when the wheels weren't moving and as a fluid device, doesn't suffer from wear. However, slipping in and out of D all the time will cause wear.
Then again, auto boxes are a bit of a mystery to me so I may be off beam here.
Sometimes I will use the parking brake, even in D, but generally the foot brake does fine.

As far as blinding the driver behind, brake lights aren't that bright. In the rain you don't use a fog light as the glare would make it more difficult for people behind to differentiate when the brake lights come on, not that it will blind anyone unless they stare at them. personally I am looking at cars further up and the traffic lights so I can anticipate what I will need to do next.

On a similar subject, I have found that in a slow moving traffic queue, if I put the g'box from S to W, the torque converter softens up making pick up softer (avoids those agressive surges forward you can get with autos) and it stays in 2nd so the crawl is faster - generally don't need any pedals as the speed seems to match the traffic!. Then switching back to S as soon as the road clears.

 

[Myros]

the manual..

..for my auto says leave it in D and use the footbrake or parking brake if the wait is for a few moments only, such as at traffic lights. You can judge how much energy the box is soaking up by the amount of creep you have just absorbed.
The only safe way to hold any vehicle at a temporary stop is in neutral with the parking brake applied correctly, and perhaps even the footbrake ready to be applied as well.
Let's face it gang, there's plenty of time to slip into D when the lights go red and amber, and by the time they are green, your handbrake is off as well.
Would you sit there in a manual car, in 1st, clutch at the biting point , hand tensed on gear lever, engine at 1200rpm, for two or three minutes, waiting for a change of lights?

 

[Silver Arrow]

Someone once told me that it cooked the transmission fluid leaving it in drive for too long. (Check to see if it has gone brown and smelly, or is still red and aromatic). I now pop mine into P if waiting at a long roadworks light, but wondered if N would be better. I must say that driving a range of US tanks in the colonies, I just left em in D and they didn't seem to mind. My 6.2 V8 diesel suburban took it OK, but my wife's 3 litre Capri cooked it. (but that was in the mid 80's and I suppose things, and Fords, may have improved since then)
George.

 

[mlc]

As always Jberks seems to have given good advise.

When I first had an auto in the late 80's I always slipped into neutral to save the gearbox. The first time I needed a gearbox service I brought the subject up and was advised (by the same specialist that I still use) that you probably do more damage moving out and back into drive than you do sitting in drive. His advise is that unless you are going to be sitting for several minutes stay indrive. As far as the use of brakes, if you are stationery for more than an instant you should use the handbrake, I think that is what the high way code says and I am sure thats what the IAM advise. Most cars have high level brakes lights and I do find them a pain in a traffic queue.

Just a final note on the comment that if you dont have the brake on you get shunted into the car in front rather than just damage to your rear - agree with the argument, but I wonder if the injury risk is lower to all concerned if you have two lessor impacts rather than one hard one - dont know the answer to that.

Mark.

 

[Myros]

I'll have just the one please

I think I'd rather just have the one shunt from behind, with the load spread out over my corpulent frame and the lovely supportive seat, than two, the second one concentrating all that energy into the area in contact with the seat belt. If you are going to hit something, hit it backwards, it doesn't hurt as much.
Given a choice, no shunts at all will suit me better. A good tip is leaving enough room between you and the car in front so you can see a bit of tarmac at the end of your bonnet and between the boot of the car ahead. Hunkered down in my SL, this gives me about 3m of clearance.

 

[jberks]

I don't quite get the handbrake/footbrake with regard to a shunt question.
Unless someone is suggesting that you sit in a queue in neutral with all brakes off (not a wise move, as you are likely to roll into something), plus anyone coming up behind you won't know you've stopped (I fell foul of that one many years ago), the parking brake is far less effective than the foot brake, both because it is less powerful mechanically and also that it only works on the back wheels (as does the gearbox P setting - so front wheels can still freewheel). So on the shunt argument, the foot brake is the only thing that might save the front bumper.

 

[chrisssl500]

Quite right. You should always leave 'tyres and tarmac' visible when in a queue.

 

[Myros]

except

any shunt serious enough to send you that far ahead is probably going to knock your foot off the footbrake as well.or it might knock you out, or a whole bunch of other things. That's why they put a ratchet on handbrakes/foot operated parking brakes, so at least some constant braking force can be left on, regardless of the driver's state. Of course it would be better if they came up with a four wheel system rather than two, but it's a cost thing, and they apply the Ford Pinto calculation to these things don't they?

 

[niva441]

The parking brake is only used for stopping the car in the event of brake failure, so 2 axle braking is adquate for that purpose. Holding the car when stopped reuires far less effort.

Most Land Rovers have a central transmission brake that is supposed to spread the load over all wheels. The reasoning for this is that is the effort divided between all wheels is less likely to slip off road. Although it used to amuse people on hills when I stopped, applied the handbrake and as I released the brake, the car rocked forward as the transmission wound up it's slack. Never happened on my 4WD Lada with a conventional handbrake and a central Diff Lock.

 

[mlc]

Well you learn something everyday, I always thought that the ratchet on the handbrake was so that the brake stayed on even when I got out of the car - now I find that its a safety item in case I get knocked out in a collision and cant hold the brake on manually

I like the idea of leaving free tarmac in front of you for safety - but here in manchester if you leave 10 feet of free space someone will overtake you! It did remind me of a one day advanced driving course that I did - which is relavant. We were told that when waiting at a junction, say a right turn for instance, you should sit in gear and with the wheels in the striaght on position. That way if you saw that you were about to be shunted from behind you could accelerate forward (hopefully in to space) and if you were shunted you would be pushed forward rather than into the oncoming traffic. So this suggests that leav it in drive and left foot braking ready to go.

Mark.

 

[pascal]

Em Mark,

I didn't do an advanced driving coarse, but was thought that when learning to drive.
It amazes me how many people go into a right hand lane, and have their wheels
pointing towards where they are intending to go. Pretty sure its in the highway
code, or one of those booklets.

Pascal

 

[jberks]

Em Mark,

I didn't do an advanced driving coarse, but was thought that when learning to drive.
It amazes me how many people go into a right hand lane, and have their wheels
pointing towards where they are intending to go. Pretty sure its in the highway
code, or one of those booklets.

Pascal

Agreed Pascal, when queuing to cross an oncoming line of traffic I always keep the wheels straight, so at least I don't get pushed across the front of them. On the knock out issue I have to add, 1) If there is no-one directly behind me, 50% of my attention is always directed behind - so no nasty surprises, (though several scary moments!), and 2) to get hit hard enough to knock my foot off the brake or me out, the brakes are not going to do much good, you are going to slide anyway - big heavy Merc or not!!.

Its an interesting physics question, if you are going to be hit, are you better with less braking so some of the momentum can be transferred, rather than soaking up as much energy as possible in the chassis? Added to that, are you better being closer to the car in front so you can use them as additional braking!?

I do have to re-iterate though, most parking brakes are hard put to hold a stationary car on a steep incline, so they are going to be amost useless to stop you flying forward in a heavy shunt. I agree Merc ones are better than many, but you can still drive with it on if you tried - else why would merc bother building in a warning beep. At the end of the day, its a manual, cable operated drum device, not hydraulic disc, so the forces it can provide are minimal. Personally, I don't think it would make any difference in a major shunt and is less likely to stop you belting the car in front in a minor one.

The foot brake did just fine when a honda slapped into me recently.

 

[JimMac]

Auto Box clutch wear

Hello, leave them in D whilst waiting, duration does not affect clutch wear. Temperature build up at low idle (750 rpm etc) is minimal compared to what the car can cope with e.g. fully loaded plus caravan up hill trying to overtake another caravan. Clutch wear occurs when clutches are engaged and disengaged as the hydraulic pressure used to do this is ramped up to give you smooth engagement and ramped down to give smooth disengagement (known as clutch pressure decay) these rates are preset by the box manufacturer in conjunction with the mb for mechanically controlled auto boxes and parameters can be varied on modern boxes depending on your driving style.

So, by putting the box into N or P and then back into P may mean that you engage and disengage the clutches uneccessarily during a journey.

The other time clutch wear occurs is if the hydraulic pressure is insufficient e.g. fluid passed its best, poor pump, filter or internal leakage and then slippage can occur as per a manual clutch where the pressure plate isn't man enough to stop the clutch slipping.

The leaving the escape route idea when sitting in a queue is great especially when it is unexpected e.g. temporary traffic lights beyond blind bends etc. But, as per one reply certain clever drivers then decide to fill that gap. Joy.