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Is it bad for your tranny?


jinxed45

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I live in an area where there are a lot of ups and downs, and I tend to drop the shifter into Neutral during downhill for better MPG.. is that bad?

Actually I believe you save more fuel by keeping in drive when going downhill. Something to do which car electronics "feeling" there is no need for torgue and almost cutting off fuel.

Not really sure how it works but this idea is used on cars for many years.

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if you check the instant economy you will see that more fuel used at neutral.

in some cases i put it at lower gear just to slow down while moving down a heel and spare brake parts

The saddest thing in life is wasted talent

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It is bad and illegal to coast out of gear.

You need to keep the vehicle in gear to "feel" the road, you wouldn't be able to make any emergency moves in a spontaneous fashion (you would have to slap it into gear real quick before being able to accelerate), and a vehicle out of gear can turn into a runaway by causing you to over use your brakes and getting them overheated.

As far as mechanically, decelerating is good for the engine, it causes the rings to flutter and helps keep them free for better combustion and oil control.

I live in the foothills of California and my daily drive consists of rolling (and steeper) hills at freeway speeds, I always use the transmission to slow me when necessary in traffic, down long steep grades, and when exiting the freeway. Transmissions are designed to do this and it does not hurt them.

When decelerating your computer shuts down your fuel to a minimum necessary to keep the engine running. Check by toggling to read your instant fuel data.

The fuel average in my 93' STS is 20.5 MPG.

-George

Drive'em like you own 'em. - ....................04 DTS............................

DTS_Signature.jpg

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The PCM will actually disable as many as 4 injectors on deceleration for fuel economy so it is probably more economic to leave it in drive.

is it same for 4.9 L ?

The saddest thing in life is wasted talent

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The legallity of this is NOT an issue, considering I am probably speeding to begin with.

The mention of legality was not meant as a "nanny" note; there are often good reasons why things are illegal. Coasting is just plain dangerous.

Coast if you want, just be prepared to pay the price for being foolish.

-George

Drive'em like you own 'em. - ....................04 DTS............................

DTS_Signature.jpg

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Thanks for all the input and information on this issue.. but does anyone know WHY neutral would be bad?

I have been led to believe that the more RPM's the more gas you are using in that gear.. is the car's in neutral, the RPM's are as low as it gets.. ??

Please correct me if I am incorrect..

I understand the whole brake issue.. as for that, I usually shift back into gear once i'm nearing the stop, THEN brake.. so, I don't think my brakes will fry anymore than if I "braked normally."

For the most part, everyone's probably right about not being safe to drop to neutral, I just want to know why.. and i'm sure others will benefit from the knowledge as well.

THANKS!

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The PCM will actually disable as many as 4 injectors on deceleration for fuel economy so it is probably more economic to leave it in drive.

is it same for 4.9 L ?

Not sure about the 4.9. thought it was a Northstar.

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I can think of many reasons why it's much more dangerous to coast down a hill in neutral:

1) Like has been said before, if you need to accelerate quickly, you can.

2) You'll use more brakes in neutral, because you can't use engine braking to control the car's speed. I disagree that you'll use about the same amount of brakes either way, because when you're in neutral, you're gaining much more speed than you would if you were in gear and using some engine braking. So now at the bottom of the hill, you have to haul you car down from a speed that might be 20% faster than if you were in gear the whole time.

3) When you're in gear, you have the momentum of the car to keep the engine running in case of a freak situation where the A/C compressor cuts on at the same time the power steering commands a lot of effort from the pump, etc. If you're in neutral, there's an outside possibility of a stall; this wouldn't happen if you were in gear.

Jason(2001 STS, White Diamond)

"When you turn your car on...does it return the favor?"

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Oh Boy! LOL How about this...... If I was a Transmission I would not want to be put in N at speed and then slapped back in gar at the bottom and demanded to preform flawlessly after my nap!

And whoever said it is illegal to be in N is correct, the saying goes, OUT of GEAR OUT of CONTROL. It's really no big deal until you kill someone and they get to looking into why it happened. And I am sure the car has the technology to tell on you.

If you are that hard up for money that you consider such a trivial amount of savings..... For safety's sake, let us start a thread where we send you money for gas. Whats your name and address so we can start sending.

MC

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Not good for the tranny says the mechanics. Least in Idaho where most of the state is up and down.

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All makes sense.. I'm not a person that cares TOO much on safety, although a little.. I'm an outlaw (haha), the legality doesn't bother.. so.. I guess the only thing BAD, in my case, is that transmission's don't like to go from neutral at a good speed to be dropped back into gear? That's all I got from this post so far as far as my question goes..

Send ME MONEY FOR GAS!! PayPal to jinxed45@yahoo.com :)

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Well in your case then, if you don't care about the safety of your or others, and scoff at the long arm of the law, then you're pretty much free to do anything out there. I just hope I'm not on the road with you.

Jason(2001 STS, White Diamond)

"When you turn your car on...does it return the favor?"

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Personal experience....not in a cadi, but in a FWD

After coasting down a hill in neutral I went to shift back into drive at about 50MPH (and I was not revving the engine when I shifted ie no load), about 1.5 seconds of being in drive the tranny let out a load crunching noise and locked up...first thought, get it back into neutral...no luck. All I can say is after riding it out and being able to get across 2 lanes of traffic to s safe stop I will never do that again.

there is something about saving $1.00 on gas to run the risk of trying to drive a car at freeway speeds with the front wheels locked that just kind of lost its appeal....although the smoke coming off the front end looked pretty cool, and I am pretty sure I scared the sh*t out of everyone in a 1/4 mile radius

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All makes sense.. I'm not a person that cares TOO much on safety, although a little.. I'm an outlaw (haha), the legality doesn't bother.. so.. I guess the only thing BAD, in my case, is that transmission's don't like to go from neutral at a good speed to be dropped back into gear? That's all I got from this post so far as far as my question goes..

Send ME MONEY FOR GAS!! PayPal to jinxed45@yahoo.com  :)

Ok buddy, I just sent your post, and emial address to:

1) Father in law (US Marshal)

2) Uncle George (FBI)

3) Brother in law (Captain, CHP)

4) Nephew ( SWAT , Sherrif's dept.)

5) Other nephew, SWAT, Sheriff's dept. (see above, his brother,)

6) 'Pete' (close friend, Captain, Sherrifs dept.)

Maybe they could all get together and come up with some kind of donation for ya..

;)

No LOL

'93 STS.. opened, dropped, wide...fast.

user posted image

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