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Technomancy => Automotive Tech => Topic started by: GooneyBird on November 07, 2011, 05:57:49 PM

Title: Questions about driving an automatic.
Post by: GooneyBird on November 07, 2011, 05:57:49 PM
My girlfriend's mom has a '90s Toyota Corolla. An automatic. It's a sad, sad car, but up until recently, the only car my girlfriend ever used. (She has a sweet little Tigra now, which we're fixing up a bit.)

The only automatic car I have driven was my dad's old Ford Explorer, and he told me to leave it in Drive all the time, unless you park it (you then use Park), or leave it idling for more than a few minutes (Park as well). The other 'options', aside from Reverse obviously, were hardly ever used. The handbrake on the Ford (was actually a foot brake, but anyway) was never used when parked, as the trans would lock up in Park and hold the truck either way.

The Toyota's the same. The trans locks up in Park. However, my girlfriend never leaves the thing in Drive. When she stops at the lights, she puts it in Neutral, and only selects Drive when the light turns green. When she parks it, it's put in Park, and the handbrake comes on. And when she's just going about town in it, she rarely uses Drive, but rather 2nd 'gear', as she says it prevents unnecessary wear on the transmission.

I don't think that she's right, honestly, but seeing as how she's been driving the mint-green (I kid you not) beast for the last 5 years, and I have very limited experience in the Fatty Ford, I think she has a point. Plus, the thing has yet to suffer catastrophic transmission failure, but that might be due to the fact that it's a Toyota from the '90s, and they simply cannot do this 'breaking down'-thing.

But I can't imagine that going from N to D a lot is worse for the transmission than leaving it in D, as the Toyota idles a little higher in N than it does in D, and so essentially you're doing a mini-clutch drop every time you put it in D to take off, including the little bunny hop when selecting Drive.

Seeing as most of you here are American, and probably have a LOT more experience driving Automatics than I do, can you explain 'proper automatic driving' to me?
Title: Re: Questions about driving an automatic.
Post by: 1fastII on November 07, 2011, 06:18:31 PM
I wish more Americans were like you.
Title: Questions about driving an automatic.
Post by: ling427ttvette on November 07, 2011, 06:23:31 PM
Putting it in neutral at a stoplight is un-necessary. Leaving it in drive is fine.

Does her car have an over drive option? Or is there just one d on the selector? I've only ever heard that running the vehicle around town while the selector is in over drive isn't necessary, and that running it in just drive is fine because you don't reach speeds high enough to need over drive for an extended period of time.
Title: Re: Questions about driving an automatic.
Post by: GooneyBird on November 07, 2011, 06:23:58 PM
Actually, I just realized I also drove djr's Jeep Cherokee when I visited him a few years ago.

Anyway, America does not have enough Ford Crown Vics to support more me's running around, trust me. :lol:

Putting it in neutral at a stoplight is un-necessary. Leaving it in drive is fine.

Does her car have an over drive option? Or is there just one d on the selector? I've only ever heard that running the vehicle around town while the selector is in over drive isn't necessary, and that running it in just drive is fine because you don't reach speeds high enough to need over drive for an extended period of time.

It doesn't have an overdrive, it's a 3(!)-speed grocery cart. So around town it rarely even sees third gear, thus prompting my girlfriend to leave it in 2nd.

If putting it in N is not needed, why is it there then? You can't tow an automatic either way I think, so just having P would be sufficient for parking, right? Or maybe coasting down long slopes or something, but then you lose whatever engine braking you would have (which is to say, not much. This is why automatics freak me out.)
Title: Re: Questions about driving an automatic.
Post by: Southern_Pride on November 07, 2011, 06:25:47 PM
I don't use od around town. Unless your on the higway, leave it in drive. And Gooney, I can find lots of crown vics for you.
Title: Re: Questions about driving an automatic.
Post by: [ChaosweaveR] on November 07, 2011, 06:57:45 PM
Going from D to N while at a light is not needed at all. Dunno who taught her that.

I had an 89 Toyota Tercel with the same three speed auto, and I dunno how slow she's going, but it would shift into third after 40mph, IIRC...Leave it in D, she's actually wasting gas doing this, as the RPMS are higher. She might even see a bump in gas mileage too.

As for less strain on the trans, that's rubbish. The damn thing is designed to use all three gears, so make use of it.
Title: Re: Questions about driving an automatic.
Post by: Delta on November 07, 2011, 07:00:10 PM
Normally in the Nismo I just keep it in D. When I was driving through the Maryland and Pennsylvania mountains I turned overdrive off to climb, but normally I leave it on.
Title: Re: Questions about driving an automatic.
Post by: James on November 07, 2011, 07:23:33 PM

If putting it in N is not needed, why is it there then?

So it can be towed.  Towing it in "gear" would do bad things like burn up the pump.

You can't tow an automatic either way I think, so just having P would be sufficient for parking, right? Or maybe coasting down long slopes or something, but then you lose whatever engine braking you would have (which is to say, not much. This is why automatics freak me out.)

Not always.  See, the Park function just engages a pawl, a small piece of metal, that simply binds somewhere in the transmission.  Fine for flat spaces or minor slopes.  Not so much if you park on a steep grade which is why you are supposed to use the parking brake before shifting into park.  Failure to do so might cause the pawl to fail or place it in such a bind that it is difficult to shift the transmission out of Park.  As for wear and tear, if she's using second because there is no need to let the transmission shift to 3rd gear with where she is driving then she is in fact doing the right thing.  Automatic transmissions wear when shifting (which is why most have an option to turn off OD and prevent "gear hunting" on changing grades) because they have a defined amount of "slip" that is necessary to shift smoothly.  More shifting = more slipping = more heat = bad.  Shifting into Neutral is also fine.  Make absolutely no difference in gas mileage (the slight increase in revs is due to the load being taken off the engine...which is obviously a benefit here) and also can prevent extra heat from being built up through the torque converter.  In other words, your GF sounds like she actually knows what she is about.  Take notes.
Title: Re: Questions about driving an automatic.
Post by: ling427ttvette on November 07, 2011, 11:15:16 PM
So it can be towed.  Towing it in "gear" would do bad things like burn up the pump.


Although not as easy in a FWD car, it's usually best to tow a car with the driveshafts disconnected to prevent any parts from moving in the transmission while the pump isn't circulating any fluid.
Title: Re: Questions about driving an automatic.
Post by: GooneyBird on November 08, 2011, 04:49:21 PM
Another thing I've wondered about is that it crawls pretty quickly. The Ford, when left idling in Drive, would eventually slowly mozey on, no faster than a slow shuffling speed (think zombie), but the Toyota actually moves immediately upon releasing the brake, and accelerates to a brisk walking speed (think busy businessman on a phone).

I can see how heat would come into play here. I've never fully understood just how an automatic transmission works (fairy dust and unicorn farts, right?), but I can imagine a torque converter would heat up when left idling. However, I'm a little concerned about the shifting from N to D, and the little hop the car does due to the revs building up in N. That just seems like it's not good for the car.

Thanks for the explanations so far, guys. Keep 'em coming.  :) I wish we had gotten some more information on how to use an automatic in Driver's Ed or something. We were told how to clutch and declutch, and how you should never shift into Reverse when the car's still rolling forwards, but what you're supposed to do when the trusty third peddle is suddenly gone no-one said.
Title: Re: Questions about driving an automatic.
Post by: James on November 09, 2011, 12:24:40 AM
Another thing I've wondered about is that it crawls pretty quickly. The Ford, when left idling in Drive, would eventually slowly mozey on, no faster than a slow shuffling speed (think zombie), but the Toyota actually moves immediately upon releasing the brake, and accelerates to a brisk walking speed (think busy businessman on a phone).


Torque converters do more than just transfer toque, they also multiply it.  Different setups have different multiplication ratios and the ratio varies with RPM.  With the smaller motor the Corolla would probably have a numerically higher ratio to aid its acceleration.  The Ford would have a lower multiplication due to having a larger engine and for towing.

The D to N shift is nothing to worry about.  It's a hydraulic system essentially so it's actually easier on the transmission and the rest of the drivetrain than a manual transmission. 
Title: Re: Questions about driving an automatic.
Post by: MiniVanMan on November 09, 2011, 08:09:25 AM
I can see how heat would come into play here. I've never fully understood just how an automatic transmission works (fairy dust and unicorn farts, right?), but I can imagine a torque converter would heat up when left idling. However, I'm a little concerned about the shifting from N to D, and the little hop the car does due to the revs building up in N. That just seems like it's not good for the car.

It's really nothing to worry about. I don't hear about too many people burning up torque converters yet pretty much everyone I know leaves it in Drive when at a stop. Neutral is basically there in case your throttle gets stuck or some other disaster happens and you need to take it out of gear NOW, or you need to push/tow the vehicle.

At idle, the torque converter won't be working hard enough to build up a ton of heat. They can take a lot more abuse than you'd think.

Hell, I ran my 96 Cutlass completely dry of Transmission fluid once because a line came undone while I was driving and I didn't notice until the Go Pedal didn't have anymore Go in it. Fixed the line and topped it off, and the thing actually shifted smoother than before. Poor man's transmission flush :lol:
Title: Re: Questions about driving an automatic.
Post by: orangeLJ on November 09, 2011, 06:11:35 PM
the issue with her using neutral at the lights would ONLY be a major drama if she isnt holding her foot on the brake while changing into drive (and if she has the revs up)

Shifiting from neutral or park into D at anything higher than idling revs isn't good for the box, but by shifting neutral to drive every time she stops, she is putting more wear on internal components as its an added in-out shift into first.

Tell her to leave it in D, holding it in second is just plain stupid IMO and would be sustaining higher RPM unnecessarily.

That all said, I doubt any of the above would really reduce the life of the transmission by a noticeable amount.

Ive rebuilt the auto box in my commodores a couple times from general abuse, ATF isnt much fun!

Title: Re: Questions about driving an automatic.
Post by: MiniVanMan on November 09, 2011, 08:54:22 PM
Tell her this, Gooney - It's an automatic transmission, it's been around for a very long time, and it was design to select drive and leave it there until you're done driving. No further input needed (in most cases).
Title: Re: Questions about driving an automatic.
Post by: NovaDK13 on November 09, 2011, 10:55:39 PM
Tell her this, Gooney - It's an automatic transmission, it's been around for a very long time, and it was design to select drive and leave it there until you're done driving. No further input needed (in most cases).
Kind of what I was thinking, if she wanted to select a gear should have gotten a manual. Either way I dont think it would cause much of a problem, and not seeing how its going to make the life of the trans any longer? I had an 81 malibu with 300,000 miles and only had a new filter replaced because the gasket had to be replaced, shifted just fine.
Title: Re: Questions about driving an automatic.
Post by: Onyx Dragon on November 11, 2011, 02:00:34 AM
I used the parking brake in my automatic just so it wouldn't sit on the parking gear.  That, plus if it gave way for whatever reason, at least the emergency brake would hold it in place on a hill or something.
Title: Re: Questions about driving an automatic.
Post by: MiniVanMan on November 11, 2011, 11:23:57 AM
I used the parking brake in my automatic just so it wouldn't sit on the parking gear.  That, plus if it gave way for whatever reason, at least the emergency brake would hold it in place on a hill or something.

That's usually a good idea, however in places where salt is used on roads in winter, it's pretty common that your parking brake cable will seize up and not release once you set it.

This happens every year here at the dealership when someone sets the parking brake on one of our older used cars.
Title: Re: Questions about driving an automatic.
Post by: Onyx Dragon on November 11, 2011, 02:01:28 PM
That's usually a good idea, however in places where salt is used on roads in winter, it's pretty common that your parking brake cable will seize up and not release once you set it.

This happens every year here at the dealership when someone sets the parking brake on one of our older used cars.

It's not just salt, my 04 GTP did it when it would be wet and then drop below freezing.  Just took out a carpenter's hammer, hit the rotor through the rims and it released.  It's a pain in the ass, but better than the alternative.  Now I have a stick shift, so the parking break gets set :lol:

EDIT: BTW, here they use that chemical stuff instead of salt.  They just swapped over a couple years ago.