I'm new to AT. I'm used to turning off the engine as I coast the last few feet into the garage. But with the AT, I notice that when I turn off the engine with the AT in Drive, the car seems to lurch to a stop.

Why does that happen? Is it bad for the transmission? It is necessary to shift into Park before turning off the engine?

 

What would happen if you turned off a manual transmission car while in low gear and the clutch engaged (foot off the clutch pedal)? At low speed I imagine this would be kind of lurchy.

I don't think it hurts the transmission but it's not kind to it.

You can't remove the key before returning to park. Power steering no longer functions. Just drive normal; leave the engine running until you're in park, then turn it off and remove the key.

 

If it's so important to you to coast the last few feet, you can switch into neutral and shut off the engine, but eventually you lose power steering and power brakes... and of course do NOT shift into park while the car's moving. That IS bad for it (and you).

 

It happens because the car is in drive mode, makes total sense to me that it would lurch--you need to switch the car to park gear.

I programmed all my doors to unlock when I get out of the car. they will not do this unless I shift to park before I turn my engine off. All doors remain locked if I turn engine off first and it is a pain to me to have to unlock them.

Another pet peeve of mine is not using the parking brake. I have a friend who never uses her parking brake-- Every time she gets out of the car it rolls. Someday it might roll over her foot.

 

Quite unusual. Just curious how long you've been driving or driving in the US for that matter. Reason is if you've been driving a while, then you are one of the rare breeds left, not to have driven an AT car. On the other hand, AT is not common nor popular in other countries, specially Asia. If you're a new driver, then, add that to your "Lessons Learned" and "Best Practices" folder.

Now to your question, maybe you should shake that habit off, some reasons of which BC already mentioned. Slamming the AT in Park while the car is moving is a big mistake. Everything locks up and not good for the drivetrain. Same thing when you shut the engine off and in Drive mode, like shutting the engine off. Fluid stops circulating, valves, switches (all electronic now) shuts down.

Most AT cars, you can't get the keys out of the ignition unless you put it in Park. Best bet, stop the habit of coasting and shutting down before you get to your driveway.

 

Why would you want to turn it off while in drive. That amount of gas you save (minimal) is not worth the damage to your transmission. You could shift it to neutral and then turn off the car and coast. But, it is not worth the hassle for the minimal gas savings.

 

shift to park with foot on brake.

set parking brake.

take foot off brake.

 

Hmm, good point. I guess I probably have the clutch down when I do that with a MT. I'll have to try it once with the MT clutch up just to find out. =)

 

how about you not do that?

 

Bad idea. Please don't try that.

 

I'm no mechanic, so I'll probably be off with some details. But I imagine it's the same reason you should leave a MT car in gear when parked. When the car is in gear, the drivetrain is connected to the engine, and the engine naturally resists turning - after all, the spark plugs aren't firing and the oil isn't circulating. The lower the gear, the better. Thus, the wheels don't want to spin freely, unlike if you left the car in neutral.

I imagine the same things happens if you leave an AT car in Drive and turn the engine off. No more spark plug firing, no more oil circulating, but the wheels are still connected to the engine because you're in gear. Thus, the engine suddenly doesn't want to turn any more, and you get the lurch.

I doubt it's really horrible for the car if you do it a few times, but the lurching can't be good for the car in the long run. I believe the best thing you can do is turn the engine off when you are at a complete stop and if you do that, it probably makes less of a difference to shift the car in Park whether the engine is on or off.

Now, if you really want to be kind to your transmission, stop the car, pull up the parking brake, put the transmission into Park, and then turn the car off. That way the parking brake is the primary holder of the car's mass, and you ease strain on the parking pawl in the transmission. You know how the car will roll a little bit if you put the car into Park and it rolls a little bit before coming to a stop?

 

Have you been doing this every day since you bought your car? How is your transmission holding up? Is it still shifting smoothly?

 

Everything locks up because there's no power when the engine is shut off.

It is very bad for the drivetrain because the car's momentum is still trying to move the car forward while the drivetrain is trying to force the car to stop.

Yes, definitely - Park mode - Parking brake... Not good to freewheel specially if parking on the streets of San Francisco... Besides you won't be able to get your keys out if not in Park...

 

It simply behooves me as to why one would want to shut off a (any) car engine just to coast into a place to park....And I'm including any country.... I wish you would explain why it is that you do this...I'd love to hear your theory behind this...

 

What you're saying here makes sense. But then I thought of another situation. I've read that when coasting (e.g. at 45mph), the ECU will cut off the fuel injection, which means that sparkplugs are not firing, and the engine is being driven by the wheels. Isn't that pretty much the same situation? But there's no lurch when the fuel is cut off during coasting. And why isn't that bad for the engine?

 

Big $$ words Vinny . Yes please BuckyFit... anticipating fervently...

 

Hahahaha

Holy shit. This place never ceases to amaze.

Please tell me you're just fucking with us...

 

It is amazing. I can't imagine some of these people are allowed to drive their Fits on open roads as well. Scary.

I suspect the OP's reason for coasting into garage is to reduce/eliminate exhaust fumes in the garage.

 

lol . where did common sense go for people.

 

Coasting is the same on a manual/auto - shift into neutral to coast.