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Automatic Transmission usage

When stopped at a stop light, which is best for your automatic transmission - leave it in drive or shift to neutral and then shift to drive when the light changes?

Leave it in gear.

Leave it in drive.

Leave it in drive.

Each time you put it in gear, all of the drivetrain components from the engine to the wheels take a jolt. They are built to withstand these jolts in normal use, but shifting from neutral to drive that often is is not normal use.

if you shift into neutral and then when the light turns green you press on the accelerator before shifting you can damage your transmission…as said above leave it be.

Case in point, my truck.
In neutral, 1500 rpm
In gear, 800 rpm

700 rpm less fuel consumption ; priceless.

Okay, I keep seeing comments like this. RPM does not equal gas consumption!
You have to factor in load as well. A car engine running at 2000 RPM in neutral will consume a lot less gas than an engine running at 2000 RPM in drive going up a hill.
In your case, it is likely that the unloaded consumption at 1500 RPM is the same as the loaded consumption at 800 RPM, unless the 800 RPM consumption is higher. It would be higher if you have electronic engine controls and they open the idle air valve (or throttle) to keep the engine from stalling.

That said. The correct answer for the OP is “leave it in gear.”

We have had several posts on this. In Tokyo, Japan, where it may take 15 minutes to get through a light, by all means, put it in neutral.

I use neutral when at one of our notorious railway crossings where a 300 car train may go by. Otherwise, I leave it in gear; it’s best for the transmission to not be constantly shifting it.

I don’t think it makes any real difference either way. I have no stats, but it appears I am not alone in that category.

As Whitey says, “each time you put it in gear, the whole drive train takes a jolt”. Just leave it in Drive.

with waiting on a 300 car train, I’d probably just shut it off

From a safety standpoint I would leave it in gear. If a situation occurs where you have to go in a hurry, you would save time by not having to shift. Plus if you took your foot off the brake you would have no brake lights showing, and this could also be a dangerous situation.

So in this respect, avoiding an accident would also be good for your transmission

Just to be argumentative, I have a general agreement if we’re just talking about what’s best for the transmission and if cars are passing by.But, being a safety freak, in a school zone or crosswalk where pedestrians are passing in front and/or light is red, I drop it into neutral. At that point, I don’t care what’s best for the transmission. Also, particularly strong “creeping” car like my 4Runner on a steep incline, towing a boat with a semi coming down the road, I’ll think twice and put it into something other than D.

In 4 low, and some strong 4wds, it’s harder to brake and near impossible to easily stop as you slow w/o dropping into neutral.

So there are exceptions…just so anyone reading doesn’t think we’re all insensitive rednecks.

How about firmly setting the parking brake? If it can hold a car on a hill when parked, it can hold the car against D. I do it whenever I drive an automatic because I don’t want it to ‘creep’. It may stretch out the cable, but cable is cheaper than transmission. There’s a reason why BMW new automatically sets the parking brake instead of shifting the transmission to neutral every time the car stops.

While do agree that shifting between D and N hurts the transmission, I don’t think it hurts anything else. Otherwise, my car should be falling apart by now as I give it a little jolt every time I let my clutch out.

dagosa, you make me wonder. If your brakes are not capable of keeping your vehicle still while it is in drive, perhaps shifting out of drive only treats the symptom of a more serious problem.

chunky_asian, if you are giving your car a jolt every time you let your clutch out, you might be doing it wrong.

I got my license in a non-synchronized manual. I know about rev matching. My point was that I’m effectively putting the car in gear from neutral every time I get going.

That’s a good catch about possible brake problem. However, I do see dagosa’s point about stopping at a red in neutral. Some people might get their foot knocked off the stop pedal when rear ended. The car then creeps toward pedestrians. That’s why I made that parking brake comment.