I have this habit of shifting from D to N when I either coast or need to come to a stop Ilike a red light). I know most people who drive autos usually don't do this, rather, they just hit the brakes.

Is there benefits from doing this? Or is this something that pretty useless?

alex

 

its useless

 

i heard its actually bad. when you just shift to neutral while your car is moving w/ automatic even if u aint gasing it.. i did that for a few weeks

 

I used to do that on my Jeep, just to let it rev a little higher when stopped with the a/c on.
When the compressor kicked in at a light, you could really hear the old piece of junk slow down!
S

 

i do this all the time. it's not useless, it can keep your transmission cooler (not that transmissions are usually pushed to their limits in a road car), but the main reason i do it is to reduce engine vibration (one of the wipers gets a nasty rattle when the engine isn't warm or at a high enough rpm when you're stopped)...

but an interesting thing: it's a requirement (so i'm told) to do this on your driving test in HK... once you're stopped, you have to slip the transmission into neutral while idling... why? i was told that it was to prevent accidental acceleration or something... i don't actually know...

anyways, i like to do it just to do it, 'cause that rattle pisses me off, and i know i'm saving gas while i'm coasting.

 

lol, Some guy with his riced out civic does this at my school, but as he slows down he pops it in neutral and revs the engine, and always has the revs up in neutral before shifting to drive, oh the fun everyone makes of him

 

if you do burnout that way.. your transmission will get hurt...

i dont want to see any nicecar like rx8 hurting ...

 

Ok.. is it bad to shift from D4 down to D3 and then to D2 as you are slowing down (like mimicking engine/transmission/throttle braking on a manual transmission car) ?

 

Its useless and unsafe. It doesn't make your tranny any cooler.

Its unsafe because you are "in control" when it is in gear versus in neutral with no control and having to rely on your reaction time AND the trannys engage time to avoid an accident if you had to move quickly.

I will admit that I occasionally do it in a drive through so that I don't have to apply as much continual pressure on the breaks which can tire my leg.

Any other reason for doing this is just silly and potentially unsafe, IMO.

Be safe and prevent damage. ;-)

 

I don't recommend it, though....

Shifting down shouldn't cause a problem as long as you PRACTICE to find out what speeds you can shift down to safely.

Otherwise you might have some SERIOUS engine breaking which could cause someone to rear end you or could cause you to lose control or cause problems for your engine, transmission, or torque converter.

 

wouldnt that just increase uneccessary wear and tear?

 

hold on a sec... first, you're wrong, it can make your transmission cooler, and secondly, this whole "unsafe" thing, as i said above, is a matter of opinion.

this last summer, we had a bit of a heat wave, and i (was, and will) take the busses to school... those thursday afternoons they'd been running most of the day in stop-and-go 32 degree heat, they'd put the transmission into neutral and rev the engine to keep it cool. i've read (i think) in the Vancouver Sun an (obviously crappy) automotive article about this, and they too listed keeping transmission temps down if in the most extreme of situations.

about the safety issue: how the hell are you going to avoid a rear-end collision if there's a car 3 feet in front of you, a car a half a foot away to your left, a curb on your right beyond which there are pedestrians?? unless you leave yourself a carlength or more infront of you at every light (how often have i seen that? never, not once) or circumstances are such that there are no cars in front of you (which means there are cars streaking across an intersection six feet ahead) or there is a free lane or something, unless you're freakin' blind there'd be no problem picking up a car which is obviously going too fast or braking too late. considering that you lose about 0.4 seconds from the transmission engagement, and maybe .2 seconds from "realizing" to "acting", i could see that as a problem in rear-end collision while at a stop... then again, i wear my seat belt, drive a safe car, am a safe distance from the airbags, a pretty sturdy young lad, and have seen a few (very slow speed) rear-enders at traffic lights, and no amount of acceleration could have ever stopped them.
as per above, you MUST do it in HK when you are stopped, which means from some perspective there is an advantage, which someone told me (they thought) it was to prevent accidental forward acceleration on their very very narrow, and crowded streets.

 

here's a link on how your average 4 speed works:
http://auto.howstuffworks.com/automa...ansmission.htm

it's a hydraulic system (meaning that shifting out of drive doesn't stress anything much at all), and when in neutral the whole contraption is just free-wheeling, rather than under a constant load from the engine idle, with the brakes held against it.

 

Gentlemen,
Here's what I learn from my high school and university days. Back in High school, there is a bunch of my friends of mine who made a habit of just shifting to neutral at a full stop and we also had a discussion about this back then. Anyhow, we couldn't agree upon anything so at the end, the guys who shifts to neutral continues to do so. Unfortunately after 4 or 5 years (now we are in University), it seems that some of them all starts to have minor problem with their transmission. I cannot remember the details now but there was a Colt, a Subaru, an Accord and a Civic in there. Problems, include minor problem with the Shifter itself, transmission not shifting smoothly from certain gear and other minor problems like that.

Now we cannot confirm for sure that it is directly relately to that shift to neutral thing or just coincidence. But my take is, do it if it is really necessary but definitely not a good habit to pick up.

 

Your city bus example doesn't do much for your argument. For one they most likely have transmission coolers and perhaps this is the main reason for the in neutral reving. I'm open minded so I'd be interested in hearing an example with a passenger car, but I don't think there is one.

For one, there is no REAL load on a tranny when you are at a stop. Come on! A load on a tranny is created from the EXTENSIVE use of high RPMs/power required to move the weight. Ever towed anything? You definitely notice the engine is in the high RPMs longer than normal which is being transfered to the torque converter and transmission.

And I'm sorry but I didn't even bother reading your entire scenario as its obvious to me that if you have the car in gear you have much less reaction time than you would if it was in neutral. Logic can tell us that no matter what theoritcal scenario you come up with.

Again... its silly! We can agree to disagree. To each his own and the risk that goes with it.

 

actually I have experienced a problem from shifting into neutral and back into drive. Back in last october I've gotten rear ended by some chick who just got her license. I can't believe she had the gall to ask me why I had stopped in the middle of the freeway. Hello!!! its called traffic jam!!!......ahem...anyways the rental car my lawyer supplied to me was a toyota avalon(damn its like driving a boat, just floats on the road) and I'd shift from drive to neutral and back to drive again during rush hour traffic. I have a habit of putting the transmission into neutral and coast. Thats how I save on gas.

Anyhow after awhile when driving the car around town I've noticed the car would stay in gear a little longer than usual and sometimes the car would jerk a little during gear change.

So my synopsis would be that putting car into neutral and back to drive is bad! BAD I tell you!!

 

i havev seen major transmission damage when shifting to N with the cruise control on. i work at a dealership and we had a customer that shifted to N while coasting down a hill on the freeway with the cruise on. the computer took it as a problem and tried to compensat. after hearing a very LOUD bang the car stalled and had to be towed in. ended up replacing the transmission. so just make sure the cruise control is off before shifting into N.