Neutral to drive?

[mhmitszach]

Would putting my car in neutral down a hill and then back into drive have any ill effects on my transmission?

[VetteOwner]

no just dont slip it into reverse or park. its called an automatic for a reason.

[GasSavers_Bruce]

Originally Posted by VetteOwner

no just dont slip it into reverse or park. its called an automatic for a reason.

Don't push the shift lock button (or pull forward on a column shift) when shifting between Neutral and Drive. This will prevent accidental shifts into Park, Reverse or the Low range. Just push the shifter back and forth.

Better yet, spend some time playing with the shift lock button and lever positions while the car is parked with the engine off to understand how it works. You should only need to depress the shift lock button to shift out of Park or to shift into Reverse, Park or the Low gears.

Going from Reverse to Drive only requires pushing the shifter back without using the shift lock button; Low to Drive is just pushing the shifter forward (to Neutral), then back (to Drive). You can also go from Reverse to Neutral using the opposite motion.

Knowing how the shift lock button works can save your butt when you're trying to panic stop on ice, because you need to have it in Neutral for the shortest stopping distance.

[8307c4]

I'm not saying you can not do it, but I am saying for transmission longevity I recommend leave it in D always, also I am saying if you shift it you do so at your own risk.

Here's the thing, even if the chances of breaking it are but 1 in a million...
Who has to pay for it if (or when) it breaks?
You think one of these hot shot shift pros here are going to spring for it?
Personally I think you have to pay for it, if it breaks.

Yes, it can go flawlessly hundreds if not thousands of times.
All it takes is one time, one mistake, one bad luck moment.
What slowed me down is the price of a rebuild, and the fact most transmission specialists say the same thing: You want fail-safe operation then leave it in D.

That having been said, I do coast in N.
Hahaha but I have to say these things, I don't want nobody crying the blues if their tranny craps out for any reason.

Originally Posted by Bruce

Don't push the shift lock button (or pull forward on a column shift) when shifting between Neutral and Drive. This will prevent accidental shifts into Park, Reverse or the Low range. Just push the shifter back and forth.

Better yet, spend some time playing with the shift lock button and lever positions while the car is parked with the engine off to understand how it works. You should only need to depress the shift lock button to shift out of Park or to shift into Reverse, Park or the Low gears.

Until it malfunctions, or I shift so fast the detent mechanism fails to engage properly thus overriding the stop between N and R. Sometimes they break, sometimes they don't work like they should, my oldest car I can shift to-from any gear any time, doesn't matter when, how, or where.

Also column shifters work different from a floor shifter, but either one...

[tomatoman]

Has anyone tried something as simple as a drivers compartment switch to electronically cut out fuel injectors at the top of a hill, effectively shutting off gas completely while leaving the transmission engaged?
The idea just struck me.
It should be a very simple idea to test.
T man
33.15 mph 94 Maxima AT, fuel cocktail, see "garage"

[kamesama980]

Originally Posted by tomatoman

Has anyone tried something as simple as a drivers compartment switch to electronically cut out fuel injectors at the top of a hill, effectively shutting off gas completely while leaving the transmission engaged?
The idea just struck me.
It should be a very simple idea to test.
T man
33.15 mph 94 Maxima AT, fuel cocktail, see "garage"

yes, search. also look under coasting with an auto trans with the engine off blowing up the trans threads.

[kamesama980]

as has been covered many times, it's fine. just don't do it at 90mph so the tranny has to rev the engine from idle to 4k rpm. basically, if you'll end up over about 2k rpm tap the gas a little to bring the revs up before shifting to neutral. this will eliminate any possible wear.

As with any component make sure you change the fluid periodically!!! not changing fluid is the #2 killer of transmissions.

[8307c4]

If you're going to do this also turn the engine off, otherwise you won't see much of an increase anyhow. I would make sure the foot is off the gas, and I speak from experience when I say you will hit Reverse at least once...

[Rick Rae]

Originally Posted by 8307c4

If you're going to do this also turn the engine off...

Consider adding a safety warning or disclaimer when you're talking about an automatic transmission.

...otherwise you won't see much of an increase anyhow.

Absolutely incorrect. The most savings come from the neutral glide -- killing the engine is incremental.

If you don't believe that, do the math for yourself. Assume for the sake of argument that an engine burns 0.3GPH at idle. If a driver can manage to neutral glide 25% of the time (and I'd say that's optimistic), 0.075 gallons per hour is the maximum additional fuel savings.

I believe in incremental savings -- a percent here, a half percent there adds up. I'm only saying that leaving the engine on does not make the technique worthless.

...I speak from experience when I say you will hit Reverse at least once...

... unless A) your vehicle has a lockout (my VW won't go into reverse if the brake pedal isn't depressed) or B) you pay attention to what you're doing.

Rick

P.S. As long as I'm mentioning disclaimers, I should point out that driving in neutral is technically illegal in a lot of places. Check your applicable laws and make informed decisions.

[MarvHein]

I would say any tranny dangers and savings may also depend on the fuel cutout and transmission logic of your particular vehicle. I'm lucky two of my three cars have onboard computers to help me weight the risk vs. the reward.

My 2000 Jaguar S-Type shows no instant mpg computer readout improvement shifting into neutral while coasting down a hill and bangs around a bit returning to drive. This is one I won't coast in neutral since there is no reward for doing so and there appears to be some damage risk.

But I saw dramatic jumps in instant mpg on the computer (99 mpg vs. 45 mpg) with my wife's GMC Yukon XL. Overall, the Yukon XL increased nearly 20% to about 15.3 mpg in its first full week of city driving with coasting in neutral.

Shifting in-and-out of drive is very intuitive if you're used to driving a manual transmission. Returning to drive from neutral usually happens when stopped at a stop light or turning a corner at very low speeds. There is no noticeable bumping or clunking from the tranny, unlike when I use the cruise control, where it often bangs quite dramatically coming out of coast on the highway. Whatever I'm doing to the transmission sure seems safer than what the designers hopefully accounted for in their cruise control system.