Does non-moving A/T car consume more fuel if...

**rion** · September 21st, 2007 06:37 PM

I don't think it will starve atf if you put more on N. measuring atf level while engine running on D, N or P have the same reading unlike not turning engine on.

I think putting it to D won't make much difference for non-efi a/t's. since it doesn't have computer or sensors to detect it is running low on power that tells it to feed more fuel to compensate the felt load.

but putting D worn out engine support by a bit, brake pads by a bit.

and I would like a faux sunroof for my car.

**Lucius** · September 22nd, 2007 01:33 AM

Originally Posted by happy_gilmore

+1 here. even though the stops are quite low like let's say, 30 seconds, it is still moving, so the load is on the transmission as well as on the brakes.

it is better if even in short stops, that you put it in neutral. you save gas, you save your brakes, you save your transmission. and besides, i think modern AT assemblies are very durable to do that.all it takes is one click of your hand.

Good one. On my mazda3, when I keep it on D then i pull up the hand brakes, it advances pa din. Mas ok kung naka N na lang, ganun din naman. Unless gusto mo ng full throttle launch

**kinyo** · September 22nd, 2007 03:17 AM

i agree about higher fuel consumption with D engaged while the brakes are applied ... it is an additional 0.5 li/hr on my car as it needs more power for the additional load

but ...

with D engaged, brakes applied and car not moving, why do you guys say it tends to wear out brakes?

if the car is stationary, there is no rubbing friction between pads and rotor, no heat generated ... how do the brakes wear out in this condition?

**niky** · September 22nd, 2007 04:03 PM

The application of brakes as you stop, and the constant pressure applied as the car is stopped. It wears out the pistons, and in some cases, can cause warpage of the brake discs if you hit traffic after a high speed run. It's not damage you can see right away, but it accumulates... lots of magazine testers and owners report warped brake discs before 100,000 kms on automatic cars.

On the other hand, I've never heard of tranny failure from putting it in neutral. Most AT failures are related to transmission fluid degradation and contamination from heat build-up due to traffic, a failed ATF pump, or excessively hard driving.

**alwayz_yummy** · September 22nd, 2007 04:36 PM

etong liteace kaya ko napalitan ng a/t kasi yung former owner ang driving habits pala nya is retain to D... mga 10 mins kami nagkwentuhan, di siya nagbother mag-shift to N or P...

so ang kalaban lang talaga ng a/t is heat--kaya siguro some are equipeed with those air-ATF coolers (aside sa those you found underneath the radiator...)

and as they said--fluid kasi, kaya mas malaki ang losses...e ang a/t fluid ang nagpapatakbo sa kanya....

parang lumalayo na tayo sa topic.....

**niky** · September 22nd, 2007 04:54 PM

Actually, we're still on-topic.

The main contention for people not to put their cars into neutral in traffic is that it wears down the transmission... which is why we're discussing it.

Another contention is safety, daw... it's supposedly safer if you can move right away at the stoplight. Personally, I'd say this depends. If you're hit from behind and accidentally release the brake, the chance of you hurtling into the car in front of you or out into traffic is greater.

**alwayz_yummy** · September 22nd, 2007 05:10 PM

ako i dont recommend leaving your AT on D--> i am a victim of being rear ended because some guy in my rear forgot that he's on D and released on his brakes!

fortunately it happend on my former lifted delica and he hit my rear under bar and luckily he did not dent it...

**Automahn** · September 22nd, 2007 06:59 PM

Originally Posted by happy_gilmore

+1 here. even though the stops are quite low like let's say, 30 seconds, it is still moving, so the load is on the transmission as well as on the brakes.

it is better if even in short stops, that you put it in neutral. you save gas, you save your brakes, you save your transmission. and besides, i think modern AT assemblies are very durable to do that.all it takes is one click of your hand.

You save on your stop light bulbs as well.;)

**rion** · September 22nd, 2007 11:04 PM

there is no rubbing friction between pads and rotor, no heat generated ... how do the brakes wear out in this condition?

like mentioned, just by a bit...

comparing our own A/T and M/T ride, mas malakas ang brakes consumption ng aming A/T.

in my case, it's faster to pickup speed on standing start traffic light to use N then flooring at D. than staying on brakes then flooring to D. because somehow when you put from N to D, you get a kicky start-up feeling. though I hear about brake torque but I have no idea what it means...