Sometimes when i go down a big hill i will put my car in N and let the revs drop. there are some big hills round here so i figure if i keep the revs low the car will save gass. but will this hurt the engine having it roll around in neutral? btw this is an automatic. i do when coming to a stop too sometimes if i see the light a little far away and just coast up. so is this bad and hurting my engine or keep on truckin. btw just hit 3,000 miles!

 

id be carfull bringing up the gas saving issue, alot of people fight to the death about that around here.

i would say your in the clear

 

no, your not doing your car any good letting it roll in neutral to a stop, especially in an automatic, and while on the highway, it is against the law to not be in a gera.

so to sum up, ALWAYS keep the car in drive, even when rolling down a hill or to a stop. that is how the car is supposed to work. you have an AUTOMATIC, which means all you decide is park, forwards and backwards. you are not supposed to select gears, with the exception of your fake me out sport shifter.

 

I find the engine to be pretty free revving and even when I try to use it to slow me down it is not great at it, and honestly if you put it back into gear while the car is moving you may be causing yourself more harm than good in the long run

 

the automatic is designed to be put in gear and left there, so you would be better off if you drive it that way... you could be hurting the transmission by putting it in gear while moving, because the rpm's won't match the speed your moving

 

yeah us 5sp guys have all the fun i coast every where i was getting about 27 but it has ben snowing here in denver and people need to learn how to drive the roads are dry yet everyone still goes 40 on the high way

 

He is not hurting the car by rolling to a stop in neutral auto or manual. Nothing will happen to the car. No one will know he is not in gear and if he is still doing the speed limit, who cares.

He is not hurting the car either by putting it back into drive from neutral after rolling down a hill. The RPM's not matching the speed doesnt matter. If you think about it, its just like a manual. When you shift in a manual your RPM's drop in the middle of a shift and then jump back up cause they dont match the speed your at. Its not hurting anything there. So he is fine doing that and is not hurting the car.

 

Wouldn't the ECU know when you're in gear and out of gear? I would think coasting to a stop in N would save you something, but no real proof to speak of pointing either way, certainly nothing cited here yet. If you just let off the gas though your injectors aren't working and you're using engine braking as well, no? I would speculate that it still wastes something since you're keeping load on the engine and/or drivetrain keeping it in gear though, again just speculation.

 

all i know is going down a hill, i will need some engine braking with regular braking.
wait... that for 4WDs vehicles.

 

by letting the revs drop your not saving any gas.

when youre foot is off the gas the ECU tells the injectors to idle. when this happens the engine is just coasting and it only uses the same amount of fuel as if it is idling sitting still. not only that but when you put the automatic in nuetral it stops lubercating parts in the tranny. when the input shaft spins and drives the pump. there fore your basicly starving the tranny of oil.

in lamens terms, yes its bad for the car.

 

I would check to see if the trany pumps when in neutral you might be over heating the trany most cars dont pump in neutral.and i dont think its good to go from neutral to drive when moving there are still clutches in auto tranys.

 

I am not sure if its bad or not but I know you will probably save your brakes some by keeping it in gear, because by letting the tranny downshift it doesn't require you to use your brakes quite as much, or at least that what I have always been told, seems like it would hurt your has mileage because there isn't as constant of a feed of fuel, the constant shifting of idle to gear wouldn't provide a steady flow to even out, just my opinion though

 

thanks guys. based on the O's i just let it stay in D. i use the slam stick sometimes but amazingly i seem to go faster and waste alot of fuel quickly..:D all that stuff about fuel injectors and such idk about im more of a visual and personal modifier on my xb. no engine stuff for me i'll just blow it up. Thanks though

 

When you set your gauge display to the "on demand MPG"... You'll notice that it will say 90-mpg or 99-mpg when you're off the gas... This is because the engine is at idle as stated before. There is absolutely no need what-so-ever to place the car in neutral at any point other than to tow it or push it when it is off.

Leave it in gear, you're not doing yourself any good.
I wouldn't say that it's doing you any harm though either.... Just causing more effort.

 

look the ONLY reason wy automatic transmissions are avaliable with neutral is for unforseen circumstances, like say the throttle jams wide open, and you can't control accelleration, you put your auto in neutral, and stop the car. or your car breaks down, and you gotta push it or whatever, you put it in neutral.

otherwise, you leave it in gear.

and yeah, even my old 95 explorer would declare 99 mpg when coasting downhill, in D, with my foot off the gas.

 

I dunno. I thought:

a. transmission fluid was constantly pumped, and is never ever disengaged by switching to neutral;
b. the transmission is electronically controlled, so switching between neutral and back to drive means the CPU will know which gear ratio is needed for whatever speed you're at (this is not a chain-linkage auto tranny);
c. switching to neutral merely disengaged the tranny from the wheels, removing torque and allowing the engine to rest in idle?

No?

No worries...Scion just needs to introduce hybrid models with CVT; then we'll never have to think about it at all - no neutral, just P-R-D!

 

if your trany pumped constantly all the time when in neutral your car would go when your foots is off the break . it pumps in 2 diff directions D and R
so witch way do you think it pumps in neutral?

 

ok ever notice that a rear wheel drive automatic is towed from the rear wheels. simple fact of it is the transmission will pump the fluid into the transmission. in order to tow a rear wheel drive car the normal way you have to disconnect the drive line or else you will seriously damage the transmission.

 

good analogy, so I take it you don't use the clutch on your manual transmission, you just slam it into gear

 

so every one who towes a suv behind there behind there big motorhome they all have to disconnect the drive lines?
thats alot of work for them older people maybe they have the car shop do it for them when they need to drive the car .