Question about Automatic Shifters

"zeontestpilot" (zeontestpilot) 05/05/2014 at 09:03 • Filed to: question

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Allright, so I have a very basic knowledge of how cars work, but I'm always eager to learn something new. So please bear with me if this is a dumb question.

My Question is this, why does an automatic transmission give you the option, like seen in the photo, to access different gears when the purpose of an automatic is to do away with the clutch and have it shift for you? I don't think you can use it like a clutchless transmission, can you?

I know for this particular model, a '09 PT Cruiser, it breaks down like this:

D (overdrive) : gears 1, 2, 3, 4

3 (drive): gears 1, 2, 3

1 (low): gears 1

Besides for hill climbing, I honestly don't see a reason why these are available. Is there certain situations why you would ever need to put the car into any other position besides D?

Torvic Vardamis > zeontestpilot 05/05/2014 at 09:12

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Towing.

Nibby > zeontestpilot 05/05/2014 at 09:13

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If you get your car stuck in snow or something... if you want more control eg, driving on ice, etc.

Tom McParland > zeontestpilot 05/05/2014 at 09:13

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As you mentioned "hill climbing" but more importantly hill decending. I have driven several mountain roads, some very steep, and rather than ride my brakes the whole way down, I use those lower gears to "engine brake" the car so it does not accelerate more than I want it to. For example on some mountains if you let gravity take control your car can easily reach 40-50 mph, I don't want to do 40mph around a blind mountain turn. If I keep the car in 2, the transmission will not let the car go past say 25mph. This saves my brakes and keeps me safe. Also, sometimes those lower gears can give you a little more traction out of snow.

miadaman? yes please > zeontestpilot 05/05/2014 at 09:14

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Mostly having the ability to access lower gears for higher torque when towing/uphill. I think the way clutch plates mate in that particular gear is different than if you were to access it through "D". Suppose to get more assist from the tranny gearing by locking different set of plates.

spanfucker retire bitch > zeontestpilot 05/05/2014 at 09:14

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Automatics from even a few years ago were not nearly as intelligent as they are now. My Matrix used to have two low gear modes I'd have to shift into, and then a button on the shifter itself to activate Overdrive (had a little O/D symbol on it).

These days, with more advanced torque converters, automated manuals (that use an actual clutch) and Dual-Clutch systems, those contrivances are no longer necessary. If you need a low gear for hill climbing, you simply shift into a low gear. Or even let the tranny do it for you; most are smart enough to recognize when you need torque for going up hill.

Mikeado > zeontestpilot 05/05/2014 at 09:20

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I think it's at least partly for snow, so the wheels don't spin up as easily.

Dunnik > Tom McParland 05/05/2014 at 09:20

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Pretty much this ^

Think of it as a manual override.

zeontestpilot > Nibby 05/05/2014 at 09:23

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I did it when we got hit bad with the ice/snow storm in MI. Though I noticed that in regular Drive (3), when I took my foot off of the accelerator the tires tended to slow down and not "cruise' for a bit like in overdrive. I quickly learned to use that to my advantage on ice, snow, or dirt roads when traction might not be good.

zeontestpilot > Tom McParland 05/05/2014 at 09:28

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What if you don't have access to a 2nd gear? I'm afraid if I do some hill climbing in the low gear (which is just 1st gear I've discovered), it will break if I red-zone it, right? I do keep an eye on the RPMs though. My car is a year below the one in the pic.

PetarVN, GLI Guy, now with stupid power > zeontestpilot 05/05/2014 at 09:29

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Another reason why you would use it is to force a downshift when driving on the freeway. If you're going to do a big lane change/overtake maneuver, knock it down to 3, and it'll hold the car closer to it's optimal power range.

Tom McParland > zeontestpilot 05/05/2014 at 09:33

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I was just using 2 as an example, it really all depends on your speed on a given slope. If you stay in "1" you won't go very fast, you will know right away that your car won't go very much above 15mph or so. 3 should be fine.

zeontestpilot > PetarVN, GLI Guy, now with stupid power 05/05/2014 at 09:33

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So can it be used for a Clutchless transmission? This car can't, no access direct to 2nd gear. But I know other cars allow you to access all the gears. Logically, its seems like I should be able to use it like a clutchless, but I don't know the inner workings of a transmission to know for sure.

TwinCharged - Is Now UK Opponaut > zeontestpilot 05/05/2014 at 09:33

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Here in Hong Kong where there are many steep hills, there are actually signs on the road suggesting that you engage low gear when going down a steep hill. Since the vast majority of cars in Hong Kong are automatic, shifting into a low gear on an auto box "locks" that low gear in place and helps in the descent by engine braking.

At least that's how I think it works…

Demon-Xanth knows how to operate a street. > zeontestpilot 05/05/2014 at 09:37

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For when you want to keep speeds low. Such as going down a long hill. Drop it in third instead of D and just let the car go rather than dragging the brakes for 20 miles.

zeontestpilot > Tom McParland 05/05/2014 at 09:39

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Alright, that's good. Thanks for the quick response though! :)

twochevrons > zeontestpilot 05/05/2014 at 09:40

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To be honest, I think that very few people actually use them! In my experience, many automatic transmissions (especially '90s and earlier ones) are very eager to get into as high a gear as possible and stay there. Being able to exclude higher gears lets you keep that behaviour under control to a degree, either for engine braking, or to keep the revs up for more power on demand (my old VW Cabrio would go into 4th at just over 30mph, and be utterly gutless, so I'd often put it in 3 while driving around town).

It isn't quite like a clutchless manual, in that selecting a lower "gear" still allows it to operate automatically up to that one – all it does is prevents it from selecting a higher gear. With a full P-R-N-D-3-2-1 selector, you could theoretically "manually" shift it up and down through the gears, holding onto each gear for a bit longer than the transmission normally would, but that isn't really the point to it.

Some modern automatics do offer something more like a clutchless manual, for example, the current Tiptronic system used by VW, Audi, Porsche and others has P-R-N-D-S (where S is for sport mode with more aggressive automatic shift points). You can move the lever sideways from D, then bump it back and forth to sequentially select gears, starting from the gear that it was in when you moved it from D. In this mode, it won't change out of the selected gear unless you hit the rev limiter, or the RPM drops too low – basically, it is a stupid-proof clutchless manual mode.

By the way, there's no such thing as a stupid question – we all had to learn this somehow!

zeontestpilot > TwinCharged - Is Now UK Opponaut 05/05/2014 at 09:41

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Well, for my car (pt cruiser), I've discovered that, like above, whatever number is on the position, the gears go up to that number. Like 3 would be 1, 2, 3. Not sure all cars are like that though, but I'm willing to bet most Chrysler cars have that setup.

PetarVN, GLI Guy, now with stupid power > zeontestpilot 05/05/2014 at 09:46

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You should be able to use it like a clutchless. I do it all the time in my brother's '06 elantra (but you can access 2nd in that car) Just be careful not to knock it down in to 1st on the freeway.

zeontestpilot > Demon-Xanth knows how to operate a street. 05/05/2014 at 09:47

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That's what I'm currently doing. I live on dirt roads, and if muddy, i put it in 3rd. If i don't have a running start for a hill, I put it in 1st. I may drive an automatic, and the*dreaded* pt cruiser, but I am always trying to improve my driver skills.

offroadkarter > zeontestpilot 05/05/2014 at 09:47

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engine braking

used in low traction areas for smooth starting (put car in 2 to start on snow to avoid wheel spin)

stuff like that, and yes you can shift the gears yourself but depending on the car it might not happen in the most dignified manor. My 85 bmw has a manual mode on the shift selector knob where it will let you control the gears yourself and will shift damn near in an instant. My marauder on the other hand has a slight delay because it wasn't intended to be used like a "sport" mode.

McMike > zeontestpilot 05/05/2014 at 09:48

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Driving in the Mountains.

Climbing : Nothing more annoying than having your transmission kick down from 4th to 3rd every 30 seconds. Put it in 3rd and hold it. (same reason a lot of cars have an overdrive on/off button)

Descending: Nothing more annoying than overheating your brakes and careening off a mountain road to your death at 100mph. Putting the car in a lower gear will allow you to use some engine braking to hold the car at speed.

Others mentioned snow driving too, but driving through the mountains is where most people will use these lower gears.

GTI MkVII > twochevrons 05/05/2014 at 09:55

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Funny that you mention older transmissions shifting to the highest gear ASAP. My 97 Civic shifts to 4th (final gear) at about 33-35 mph. With only 106 lb ft of torque, you can imagine how anemic things feel lol. Funnily enough though, D3 on my gear select is referred to as "city/sport" mode in the owner's manual.

zeontestpilot > twochevrons 05/05/2014 at 10:00

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Ah, thanks, I'm always worried about asking a stupid question, because I'm still new to cars, but I'm eager to learn. And thanks for the in-depth answer too.

And I will admit, I drove my parents '00 Malibu like it was a stick. Since I never drove a stick before, but was very curious, I had a friend give me some pointers and I shifted it at about 3000 to 3,500 rpms to get a feel for it. I also drove my mom's Kia Rondo, which had an autostick feature, thought it was as fun as drivng the Malibu and physical moving the shifter.

I want my next/replacement car to be stick, but my wife doesn't know how to drive it, nor do I have enough experience behind the wheel to justify the purchase right now. So I figure, learn more about automatics, at least be a proficient driver with what you're given. :)

TwinCharged - Is Now UK Opponaut > zeontestpilot 05/05/2014 at 10:01

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Some other cars have more advanced systems I think. For example, the Mercedes W220 E-Class has the option of PRND432.

E92M3 > zeontestpilot 05/05/2014 at 10:05

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Mostly for hill descent. Try going down Pikes Peak in a regular car only using your brakes. They actually have a person stationed at the bottom who measures your brakes with a temp gun (should you ignore the signs and actually make it to the bottom). Over a certain temperature and they won't allow you to drive home until they have cooled down.

Logansteno: Bought a VW? > zeontestpilot 05/05/2014 at 10:07

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I know in my dad's truck and my van 3 is used for towing duties.

2 and 1 are for snow and engine braking.

Jake - Has Bad Luck So You Don't Have To > PetarVN, GLI Guy, now with stupid power 05/05/2014 at 10:08

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I do this all the time. My car has PRND321 and I quite often start in "1" or leave it there when doing things like autocross or getting onto onramps. My car is 14 years old but still smart enough to shift up even if I leave it in 1 and try to go faster than my redline, which makes "1" more like "stay in the lowest gear physically possible without breaking the engine", and very useful for racing.

zeontestpilot > E92M3 05/05/2014 at 10:11

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Curious, but its for there safety so I can understand that.

Saabaru > twochevrons 05/05/2014 at 10:16

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Saabaru > twochevrons 05/05/2014 at 10:16

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Burnouts.

Janson Rodger > zeontestpilot 05/05/2014 at 10:36

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I had an automatic Escort that had Low, Drive and Overdrive. If you started it in L it would hold first gear, then you could move the lever to Drive and it would shift to second, you could then shift the lever back to Low and it would hold second. Back to Drive for third, then to Overdrive for fourth. Rarely did I use that as just Drive/Overdrive on the highway was enough.

If only EssExTee could be so grossly incandescent > zeontestpilot 05/05/2014 at 11:49

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The transmission will do an emergency upshift at redline to avoid over-revving, and it'll drop back down as soon as it's safe. Putting the transmission into Low doesn't really hold it in first, it's more like it just raises all the shift points as high as possible.

zeontestpilot > If only EssExTee could be so grossly incandescent 05/05/2014 at 12:06

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I haven't ever go that high in RPMs on my car in the 1st position, but it doesn't seem to shift to 2nd. The manual says its suppose to shift to 2nd gear, and that the 1 position is the low gears, but I've never heard it happen. It may though, since I aim to not put too much stress on it and not to push it.

twochevrons > zeontestpilot 05/05/2014 at 13:20

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In practical use, there's not a whole lot of difference between Tiptronic-style shifting and the gear-select mode on a "normal" automatic. I've never come across a need to force an automatic to change up, so, in practice, limiting the maximum gear works the same as explicitly selecting one. Both can be fun, but Tiptronic (and systems like it) is better-suited for driving like a manual - you can just bump the lever back and forth, rather than have to move it into the next detent without overshooting.

Driving an automatic transmission 'manually' like that definitely is a good way to get a feel for how shifting gears works - giving you an idea of when to change gears, and how your car pulls in different parts of the rev range. That said, the torque converter is still doing a lot of work for you, and the only way you're going to learn clutch control, and how to shift smoothly, is by having that third pedal ;). I personally prefer manual transmissions for 'fun' driving, but I don't have any issue with a good automatic. My wife hasn't had much experience with manual transmissions, and really wants to start driving our MGA, which is, of course, very manual - she's also using Tiptronic as a jumping-off point, until the weather gets good enough that I can dig the MG out of storage and find a parking lot to practice in!

zeontestpilot > twochevrons 05/05/2014 at 14:23

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It did give me a good idea of how the car shifts and where to shift. Of course, I started to learned the basics of a manual on my wife's friend's son's, '8x vw rabbit pickup, which was mid-way through a resto, so none of the gauges worked! Still an awesome truck.

My original plan was to for our current car (a pt cruiser) to become a secondary car, once we got another one that was stick because 1. i want to drive stick, 2. i drove long distances so MPG. our little cruiser was going strong until I brought it to MI (from FL), now we keep having issues with it. Right now, it does not like to drive straight all the time, and now the windshield wiper fluid stopped working....again...it's becoming a pain in my neck with stupid small repair bills adding up.

So I have two choices; keep it and suffer, because it's my very first car and close to my heart. Or trade it in for a better car, which will have to be automatic, since (and i love my wife) she won't have the patience to learn stick right now. I'm thinking its going to be the latter....which stinks....

I've been meaning to write a post to ask oppo's opinion on good, reliable cars; I just haven't got around to it yet.

Rico > twochevrons 05/07/2014 at 09:20

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I've got one of these Tiptronic style systems in my car but seriously I have no clue how to use it. My car salesman was equally stumped with my questions so he just said "Don't worry about it most people never use it" but I would like to know how to. Maybe you could help?

Basically my questions are when using Tiptronic if I am approaching an area where I need to slow down and I'm in 4th gear do I downshift 3-2-1? Do I just apply the brakes?

If I do need to downshift 3-2-1 do I do it slowly? Do I just pull 3 times really fast to get to first gear?

When shifting do I let off the gas then shift? Or do I just shift away? None of this is explained in the manual and a million google searches bring up different answers.

twochevrons > Rico 05/07/2014 at 10:27

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I'm by no means an expert, but at least on my VW Golf, there seems to be an awful lot of "brains" behind the Tiptronic system. It doesn't always shift exactly when commanded, rather it will delay the shift slightly and/or rev the engine if necessary, in order to keep the shift smooth, so there's no reason to lift off while shifting. That being said, you will get the smoothest shifts if the throttle position is 'just right' for the engine speed and load. You just have to get a feel for how your car behaves in order to find that sweet spot – very much like learning when to shift with a manual transmission.

As far as downshifting, at least in my car, there isn't much need to downshift to first. It will pull fine from second at a crawl, and even in Tiptronic mode, it will automatically select first when you come to a stop – part of a larger system that will override the manually selected gear if the engine speed is too high or low.

I don't think that it is possible to skip gears with VW's system - downshifting in quick succession always seems to hit each gear, at least briefly. I'd recommend downshifting in conjunction with the brakes as you slow down, keeping your engine speed in that 1000-3000 range (or whatever applies to your car) where it pulls strongly, but isn't too high – again, just like with a manual transmission. You could downshift more aggressively, keeping the engine speed higher, in order to use engine braking, but that can be tough on the transmission, and isn't really necessary in normal driving.

The same thing could really be said about Tiptronic in general – modern automatic transmissions are so good that there are very few situations in which you need to override the selected gear. That said, it can make driving more fun – being able to select the right gear (particularly downshifting) in advance, rather than once the transmission realises that you need it, lets you make the most of your car's performance, and, in my eyes at least, makes you feel more 'engaged' in the driving experience. I don't usually bother with it when driving around town, but on a nice twisty back-road, Tiptronic is the next-best thing to a manual transmission.

Hope this helps :) As I said, I'm not an expert, and what works for me and my car might not work for you and yours, but if there's anything else you'd like to know, go for it!

Rico > twochevrons 05/07/2014 at 13:54

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Your post was rather informative! Thanks!