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Automatic transmition shifting to neutral when slowing down

I have a relative that does this allot i didn’t think was a good idea he said it don’t hurt anything, and get better millage. Can this hurt anything, or actually help with mileage other than maybe coasting with it in gear?

Sure. It doesn’t say to do it the manual. It says to use engine braking when ever possible and even use the downshift capabilities. Cars are made to operate according to the practices advised in the manual. Slapping it in and out of neutral cannot be the greatest hing for the transmission. How much gas do you think your relative actually saves. Now multiply that by the price per gallon and subtract that from the cost of a transmission repair/ replacement. That actual savings don’t look so good anymore.

This isn’t something I’d worry about either way. I don’t think it hurts anything; likewise, I don’t see that it helps anything. Very much anyway.

It’s true though that when in neutral the driver has less control of the car, harder to slow down quickly, and harder to accelerate to get out of the way of something coming towards you. Coasting in gear saves gas too, so there’s not much reason to coast in neutral in most cases. Just coast in gear instead.

There is one situation where I’ll switch from D to N, where probably other’s don’t. My Ford truck has an automatic and I tend to put the transmission in neutral as I approach a stoplight that I know I’ll be sitting a while before it changes to green. While stopped, it’s easier not to have to keep putting my foot on the brake to prevent the truck moving forward. I think it is slightly safer to have the transmission in neutral in that situation, stopped at a red light, as if the driver gets distracted and remove his foot from the brake, the vehicle won’t move forward due to engine power and go into the intersection or run over a pedestrian.

Doesn’t hurt anything except perhaps to put more wear on the shifter mechanism. Modern automatics are shifted by the computer (the Transmission Control Module) and their programming will not allow them to hurt the tranny.

Doesn’t do any good, either. I agree with dag when he says your relative should just drive the car the way the owner’s manual recommends. I know of absolutely no study that has found an increase in gas mileage by shifting into neutral when slowing down.

Modern cars shut off the injectors when coasting in gear. Coasting in neutral uses more gas. I would also agree that, overall, the difference in mpg would be hard to detect.

This is what i have kind of thought. A few times he’s done it then went to go and revs the motor trying to go then has to shift and take off. I honestly think it’s pretty silly a hill maybe it would be worth it even then it’s probably hardly any different.

I think most the cars he did it with had mechanical shift as they had the lever type shifter. Maybe those are electronic too. First electronic shift i saw is a 1014 ram where you turn a knob on the dash.

A 1014 ram is one rare vehicle.

I meant 2014

Actually, automatic transmissions have been electronically controlled for many years. They’re designed to feel like you’re doing the shifting, but you’re just telling the TCM what you want it to do for you. It’ll still protect the tranny and engine should you try to tell it to do something destructive.

Manual trannys have few such protections, but if you don’t have a clutch pedal, you don’t have a true manual.

I do have to add that attempting to correct the driving practices of another isn’t usually well received. Unless the habit in question creates a safety hazard (this one doesn’t except in the rare instance where he/she might suddenly need the ability to accelerate out of danger, it’s generally better to just respect their practice.

There IS however, that slight likelihood that the ability to accelerate might be a good thing… the probability will be largely depending no your relative’s driving environment.

@VOLVO V70: I can’t help but notice that your (usually well-thought-out) comments here have, of late, been noticeably sub-par; to wit, three of your last four posts have amounted to little more than snarky retorts of others’ spelling and typographical errors.

Given this departure, I’m worried: is it possible that this–seemingly harmless–short temper might be a sign that there is something physically amiss? Some personal infrimiry, perchance of a periodic nature, that is souring your mood and emotions?

At any event, here’s hoping that it clears up soon! Before you know it, you’ll be swimming again!

In this day and age, shifting an auto in and out of neutral just makes the engineers who design the cars cringe while the service. departments and parts manufacturers just smile.

Coasting in neutral is illegal in some states, presumably because it reduces your ability to accelerate away from a potential crash.

Coasting in neutral probably won’t hurt the transmission. However, shifting back in gear would require the clutches inside the transmission to slip more than they normally do. Those clutches have to bring the idling engine up to speed when the driver shift back into drive from neutral. If the car is stopped at a light, the gears would be spinning with the engine and have to be stopped by the clutches

IMHO added wear or not aside. I thought people who buy cars with automatic transmissions don’t want to do the shifting. But apparently some just want to play with the shifter anyways.

I like to play with my shifter. I commonly downshift to slow, and when driving on a slower road, especially if I’m behind a driver that keeps slowing down then speeding up. It’s easier than continually braking. I also often use a lower gear when zipping around a busy city. Once recently when trying to get a ladyfriend to her credit union before they closed, I drove 30 miles on the highway… having forgot to upshift from third. No biggie, but I’m sure my gas mileage suffered a bit. I suppose that fits the category of “distracted driving”. The old man ain’t dead yet, that’s for sure.

@PvtPublic‌, I agree. If I’m to buy a car with an automatic, I wouldn’t want to know which gear it’s in or which gear to change to. Why would I want to spend extra money to buy a transmission that is supposed to shift itself and then guide it’s every decision?

Tom and Ray adressed this once on a show some years ago. Whenever you shift from neutral to drive, all of the components in your drive train go from at rest and loose to tightening up. Think of it this way. Almost all of the mechanical connections in you vehicle, from the trainsmission to the drive train, axles, bearings, etc have just a little bit of “clearance” built into them. whenever you shift from neutral to park, all of that “clearance” tightens up. This is normal. Whenever you shift back into neutral, all of that “clearance” comes back. If the driver is constantly shifting from drive to neutral and back, the drive train tightens, then loosens, then tightens back up again. It can be argued you’re actually causing MORE wear to those components, especially CV Joints/universal joints, along with gears. I say leave it in gear, and don’t worry about it. Or buy a stick, if you need something to play with.

T&R may have discussed it, but if your summary of their discussions is accurate, I disagree with them. I plan to continue playing with my shifter whenever I feel the urge and I’m confident that I’ll get yet another 220,000 trouble-free miles out of the tranny… if the rest of the car lasts that long… and if I live that long.