coasting in nuetral in toyota

Joined
Apr 11, 2004
Messages
3,831
Location
los angeles
Yeah, i know, about the safety and the legality issues,but does anyone know if it will damage the trans if i coast downhill in neutral on this particular trans? It's a 95 Camry5sfe. Again, no "Why would you do that" "why would you want to?", "It's illegal" responses.
 
Joined
Jan 10, 2008
Messages
4,998
Location
Milwaukee, WI
If the engine is running, then no issue. If the engine isn't, nothing is circulating the atf and there is a chance something could overheat, though I doubt it would be an issue unless you had a really big hill. A good place to learn more would be an RV forum, where towing things in neutral for long distances without the engine running is a concern.
 

JHZR2

Staff member
Joined
Dec 14, 2002
Messages
46,583
Location
New Jersey
I assume this is an AT equipped car? 4-speed? My father has always coasted in neutral in the 94 previa. It has over 220k miles and the transmission shifts like new, all original.
 
Joined
Apr 13, 2009
Messages
3,735
Location
Miami-Dade County
I usally coast in neutral when I am waiting to pay for my parking at the city garage..Its on a downgrade and sometimes you are just sitting in the same spot for long periods at a time before you can move again.
 

daves66nova

Thread starter
Joined
Apr 11, 2004
Messages
3,831
Location
los angeles
 Originally Posted By: JHZR2
I assume this is an AT equipped car? 4-speed?
yes it is,4-spd auto. So all safe then?
 
Joined
May 6, 2005
Messages
6,945
Location
San Francisco Bay Area
 Originally Posted By: daves66nova
 Originally Posted By: JHZR2
I assume this is an AT equipped car? 4-speed?
yes it is,4-spd auto. So all safe then?
Theoretically safe as long as you're going forward. However - coasting in neutral is generally a better idea in manual transmission cars. I also thought that one potential problem could be an accidental shift into reverse (I know there's usually a lockout) when the intent is to shift into drive. There's very little penalty to actually staying in drive for that kind of waiting. I sometimes coast briefly with a manual transmission, but I frankly wouldn't bother with an auto.
 

JHZR2

Staff member
Joined
Dec 14, 2002
Messages
46,583
Location
New Jersey
 Originally Posted By: daves66nova
 Originally Posted By: JHZR2
I assume this is an AT equipped car? 4-speed?
yes it is,4-spd auto. So all safe then?
I'd imagine that they are two different ATs, since the previa is RWD and the camry is FWD. Didnt consider that before.
 
Joined
Oct 18, 2007
Messages
3,756
Location
CA
If the engine is running it shouldn't hurt it. Without the engine, with a couple exceptions it will have no lube and will quickly burn up. Enjoy the worse gas mileage coasting in neutral instead of leaving it in gear.
 
Joined
Jun 3, 2005
Messages
16,116
Location
Santa Barbara, CA
on a manual trans car, they assume there is added time in order to hit the clutch, rev match and throw the car back in gear. personally in an automatic car i leave it in drive and let the trans figure it out. on my volvo i usually left foot brake and just keep downshifting until 2nd.
 
Joined
May 7, 2004
Messages
10,910
Location
Nokesville, VA
 Originally Posted By: wirelessF
Why is it illegal to coast in neutral?
One possible reason is that the engine could stall, leaving you with no power steering or brake boost.
 
Joined
Sep 23, 2008
Messages
9,905
Location
Ontario, Canada
 Originally Posted By: BuickGN
If the engine is running it shouldn't hurt it. Without the engine, with a couple exceptions it will have no lube and will quickly burn up. Enjoy the worse gas mileage coasting in neutral instead of leaving it in gear.
I'm pretty sure that unless you need to brake on the hill that you should get better mileage in N. My mostly OBDII 95 auto Neon doesn't do engine cutoff either at normal driving rpms, typically I get about 3.5L/100km coasting in D vs. 1.8L/100km coasting in N, plus the drag of turning over the engine cuts the coasting speed significantly. My only real concern is shifting back into D at 55-60mph, I rev match so no lurching but someday I should talk to a tranny tech to get their opinion of how much extra wear(if any) occurs. I want to do a manual swap eventually anyways but on preferably on my schedule...
 
Joined
Sep 23, 2008
Messages
9,905
Location
Ontario, Canada
I have a scangauge2, it shows instantaneous mileage. On my manual tracker it shows fuel cut out almost instantly if you get off the gas above 1300 rpm. On the Neon I've only seen it at 3 or 4,000 rpm and up. For my last autocross race I had the muffler off and their was the odd crackle when decellerating from high rpms.
 
Joined
May 7, 2004
Messages
10,910
Location
Nokesville, VA
The problem with the Scangauge2 is that it doesn't use fuel injector pulsewidth information because that is not a standard OBDII PID. (It's manufacturer specific). I believe it calculates fuel economy based on MAF and/or MAP readings, and the fact that you must set the engine size for best accuracy with the Scangauge2 is more evidence in that direction. Most all fuel injected vehicles do cut fuel during deceleration. It reduces emissions and increases fuel economy. There are some situations where there may be fuel injected during long periods of deceleration to keep the cats warm, but for the most part the fuel is cut off. When my Saab 93 is decelerating in gear, it's pretty noticeable when the fuel is turned back on at around 1000RPM. I don't know if that's a bug or a feature...the Fords I've had, it wasn't noticeable at all, but maybe Saab's thinking is that the driver ought to know when it's time to push the clutch in before the engine stalls. On the pre-OBDII EEC-IV Fords ('91 Escort, '95 Contour) I looked at with a DLC-compatible scantool (the AutoXray) that showed fuel injector pulsewidth, the pulsewidth went to 0mS during deceleration. I wasn't happy to find out that OBD-II scantools usually cannot get fuel injector pulsewidth information because it is manufacturer-specific. I have one that can get pulsewidth information from Fords, but not from Saabs. Oh well. So...to summarize...the Scangauge II can't tell when the fuel injectors are turned off (pulsewidth 0). At least on most vehicles. It might be capable of getting it on some, but I've never seen any evidence to indicate that is the case.
 
Joined
Sep 23, 2008
Messages
9,905
Location
Ontario, Canada
I was aware that the SG2 can't monitor the fuel injectors directly but it seems to know when my tracker has cut fuel and when it starts adding it again at 1300 rpm. It registers fuel usage again at the same time the engine starts to pull again. How? I don't really know but maybe it picks up something to do with the long term fuel trend? ie data is being collected again? I know for sure than in a manual car you'd always want to coast in neutral if you were pulse and gliding on a flat road. Also I'd bet the auto on a 95 camry drops out of lockup with no throttle so the engine has to have gas to maintain idle speed atleast as I think the engine would stop as its below the stall rpm of the torque converter? I don't really understand all the intricies of automatics and I'd think there are several different ways they could be run so probably you can't generalize what's best for every car.
 
Joined
May 7, 2004
Messages
10,910
Location
Nokesville, VA
It might sense the additional flow through the MAF or the decreased vacuum at the MAP as the idle air control valve is opened when the engine drops below 1300RPM. The Fords, as I recall, keep the idle air control valve closed during deceleration, and open it again as the engine speed drops closer to idle. As far as the transmission on the 95 Camry, it depends. Most with an electronic torque converter lockup unlock it only if the brake is pressed or the accelerator pedal is pushed beyond a certain limit. They don't automatically unlock it because the throttle is closed. The tachometer would be a good way to see what's going on with the foot off the gas.
 
Joined
Jul 26, 2005
Messages
313
Location
Lugoff, SC
 Originally Posted By: y_p_w
 Originally Posted By: daves66nova
 Originally Posted By: JHZR2
I assume this is an AT equipped car? 4-speed?
yes it is,4-spd auto. So all safe then?
Theoretically safe as long as you're going forward. However - coasting in neutral is generally a better idea in manual transmission cars. I also thought that one potential problem could be an accidental shift into reverse (I know there's usually a lockout) when the intent is to shift into drive. There's very little penalty to actually staying in drive for that kind of waiting. I sometimes coast briefly with a manual transmission, but I frankly wouldn't bother with an auto.
This is why you can shift from drive to neutral and back again without having to press the shifter button in. You can also slide from reverse to neutral to drive without pressing in the button. However, you can not go back to reverse once you have slid the shifter into neutral. And, on the flip side, L to 2 to 3 to drive (depending on how many gears you have) doesn't require pushing in the button. (I am REALLY tired and can't remember the name of the button, I think it's a detent, but meh, you know what I am talking about.) So, you CAN shift between neutral and drive without worrying about hitting reverse.
 
Last edited:
Joined
Oct 18, 2007
Messages
3,756
Location
CA
 Originally Posted By: KLowD9x
 Originally Posted By: y_p_w
 Originally Posted By: daves66nova
 Originally Posted By: JHZR2
I assume this is an AT equipped car? 4-speed?
yes it is,4-spd auto. So all safe then?
Theoretically safe as long as you're going forward. However - coasting in neutral is generally a better idea in manual transmission cars. I also thought that one potential problem could be an accidental shift into reverse (I know there's usually a lockout) when the intent is to shift into drive. There's very little penalty to actually staying in drive for that kind of waiting. I sometimes coast briefly with a manual transmission, but I frankly wouldn't bother with an auto.
This is why you can shift from drive to neutral and back again without having to press the shifter button in. You can also slide from reverse to neutral to drive without pressing in the button. However, you can not go back to reverse once you have slid the shifter into neutral. And, on the flip side, L to 2 to 3 to drive (depending on how many gears you have) doesn't require pushing in the button. (I am REALLY tired and can't remember the name of the button, I think it's a detent, but meh, you know what I am talking about.) So, you CAN shift between neutral and drive without worrying about hitting reverse.
Every car is different. On my TL I can definately shift into reverse by accident. It has no button, just a brake interlock.
 
Top