I should probably have to turn in my Man Card after asking this, but it’s something that’s been bugging me for awhile.
I’m the proud new adoptive parent of an '01 Corolla CE, with the three-speed automatic transmission. Like all of my other previous cars, this one didn’t have an owner’s manual when I bought it.
I know what drive is for: making the car go forward. I know what low gear is for in a vehicle that’s not supposed to be towing anything: better torque on slick, usually snowy roads, especially when you’re trying to go uphill without much momentum.
But what the heck is “Drive 2” or “Second Drive” or whatever for? I experimented with it (briefly) while puttering around the side streets on my way out to the interstate this morning, and I didn’t notice much difference.
Bonus question: When I want to shift from “drive” to “low,” is it better to come to a complete stop, or can I just take my foot off the accelerator and do it? I’ve always thought for some reason that the various itty bitty peices in an automatic aren’t nearly as hardy as a manual clutch, so I should only shift from a stop. My wife counters that I’m a big sissy, and I should shift on the fly. Which is it?
Unless driving under specific circumstances such as snow or towing a big load on a grade, you put it in Drive and that’s that. Set and forget.
Drive2 is like a semi-manual. It will prevent the auto box from seeking a higher gear, but unlike a manual it won’t stop it from selecting a lower one.
Don’t worry about it. Tell your wife she’s wrong, and not to sweat.
If it’s automatic then it does the shifting for you. In the instance where you want to force a gear, then you can select it on the fly. If you are going fast and bump the lever into 2nd, then the engine will rev up to match the speed of the transmission. I can’t think of many situations where you would want to force it back to 2nd, or prevent it from moving to 3rd.
BTW, you can find manuals around if you are interested…
“Drive,” on almost any car, means it starts in 1st gear and automatically shifts up. “D” means it shifts up to 3rd gear. “D2” means it shifts up to 2nd gear. Cars with 4-speed automatics use “D4” (e.g. Honda) or “OD” (= overdrive) to indicate shifting up to 4th gear. “1” or “L” (low) means it stays in 1st gear. “2” means it stays in 2nd gear (i.e., it starts out in 2nd gear and stays there).
That’s the general rule. I’m sure there are some exceptions, because heaven forbid every car manufacturer did it the same way. For example, years ago Ford had a 3-speed automatic with “D” (regular drive), “D” in a circle (not overdrive – it started out in 2nd and shifted up to 3rd) and “1.”
Downshifting to low gear on the fly runs a risk of breaking something. If you were going 60 mph and selected 1st and it actually engaged 1st at that speed, it could overrev the engine and/or subject the transmission to a heck of a shock load. Generally, automatics are designed so they won’t do that – they don’t downshift into the selected gear until a certain compatible road speed is reached. But given the potentially huge expense if something does happen, and the questionable need to shift like that anyway, I wouldn’t do it. You don’t have to be at a stop, but I’d suggest being at a reasonable speed for the gear selected.
You aren’t putting appreciably more wear and tear on an automatic transmission when you shift from D to 2 (or S, some manufacturers put “S” to mean the same thing), or, for that matter, to “L” or “1”.
The automatic transmission lever switches a valve to a position that no longer lets the pressurized hydraulic fluid move the valves & whatnot to a position that lets the tranny upshift.
If it is safe to do so (determined within the tranny by the existing pressures which in turn are a product of speed @ current gear), the tranny will drop to the requested gear (from 3rd or higher to 2nd in the case of “2” or “S”, or from 2nd or higher to 1st in the case of “1” or “L”); otherwise, if the existing pressure mandates otherwise (meaning the speed is too high in the current gear to downshift), it won’t. Abruptly throwing your gearshift lever into “L” at 110 MPH will not cause your transmission to switch to 1st gear unless something is badly wrong with your transmission.
I’m not going to call you “wrong” but it should not do so (IMHO) and I’ve never used an auto-tranny car that did so. The main purpose of the lower gear-settings is specifically to prevent such an upshift, using the engine compression as a means of limiting the automobile speed. It’s useful when descending hills and useful in slippery conditions. Also useful in some heavy-traffic conditions when you want feather-touch responsiveness from the accelerator, to accelerate and decelerate in very tiny amounts, e.g., while merging, etc.
You could do damage to a vehicle by putting it in “L” and flooring it and running the engine way out beyond the red line, but you could also do such damage by putting it in “D” and accelerating to way out beyond red line in high gear (it just takes longer). You’re far less likely to damage your engine (or tranny) by putting the vehicle in “L” or “S” and having the weight of the vehicle descending the hill force it to a speed beyond what it was intended to run at in that gear, and generally if you were in such a situation that might well be the lesser of two evils anyhow.
Slightly off topic but when the road is slick you don’t want more torque, you’re more likely to spin wheels.
An auto tranny will automatically downshift if you get on the gas, giving you more power such as for passing or going up a steep hill. You can get that power by dropping to 2, although as mentioned, watch the RPMs. You don’t have to stop any more than you would have to stop if driving a stick.
How many production cars with auto trannies can actually pull redline in D, especially when most of them have overdrive now?
I’m a fossil from the era of rear-wheel drive vehicles. A lower gear in icy or wet conditions meant that you could use engine drag to slow the car safely, putting smooth and continuous resistance to the rear wheels while the steering (front) wheels remained responsive. In contrast, if you tried to slow the vehicle by tapping the brakes, you ran the risk of losing steering (the front wheels partially or fully skidding = not much response to sterring) or fully breaking the car loose (hitting brakes too hard, hydroplaning or skating)
It’s of considerably less use with front wheel drive cars, and aside from that brakes work better than they used to.
will place the car in 1 or 2, used when the tranny shifts between 2-3 multiple times due to the speed you are traveling. going down hill and want to use engine braking, or want to place the car in a lower gear manually for situations which require it (passing, getting by school buses before then turn on those dreaded red flashing lights).
Will lock the car in 2nd gear, which can be used in the above, but also allow you to start from a stop in 2, which is helpful sometimes on ice or snow.
Also all the cars I have driven will NOT override this, if you excede the redline it will either let you or engage a rev limiter, it will NOT shift you into 3rd. You COULD damage your car if you exect it to.
Only if you are exceding the redline, All AT’'s I know of are not only able to be downshifted on the fly, and designed to be able, if you excede the redline you do, this could happen just as easially with a stick shift.
Huh. Are you sure? I’ve never seen this. I thought that in all automatics, if you put it in second, it will still start moving using first, and won’t shift into third.
You said ‘Depending on the tranny’. Do you know what manufacturers do this?
I’ve never seen a car overide this either.
Another reason you may want to use 2nd, or turn off overdrive is when the transmission continues to shift between the two and can’t find it’s ‘sweet spot’. Typical when pulling a long hill/mountain pass.
If you mean “D” instead of “OverDrive” then quite a few.
A lot of relatively modern cars hit their top speed by going: 1, top of 1st, 2, top of 2, 3, top of 3, middle of 4th, top speed a few thousand RPM below top of 4th.
A bunch of cars can do that. What makes it far from universal is the fact that many carmakers will artificially limit a car’s top speed in order to use cheaper tires on it.
My 2002 Mercury Sable can probably top 130, but it’s been governed to right around 108. That lets Ford give it tires rated for 112, which are $50 or more per rim cheaper than tires rated for 149.
My 1996 Chevy Caprice had a certifiable stop speed just under 140, but was similarly governed to right around 108, likely for similar reasons. The same vehicle in police trim or “sporty” trim as a 1996 Impala would happily break 135.
In my Caprice, “2” meant to use 2nd gear. No 1st gear, no 3rd. I never tried flooring it and going to the top of 2nd to see if it moved to 3rd. 2nd gear was particularly useful in traffic, parades or funeral processions, as it decreased your torque to the rear wheels and allowed you to spend less time pushing down hard on the brake pedal. It would also have been handy for purposes of starting out on ice or snow without spinning my wheels, although I only used it for that four times per winter.
Regarding shifting down to 1 or 2 when attempting to slow your car on ice or snow… try not to. I gigitygitygity near wound up doing a 180 one time when I did that. If your traction’s bad enough, the downshift may apply TOO MUCH braking.
Never knew that. I always though that 2nd would prevent 3rd but not 1st. You and Kancibird agree on this.
I drive manuals, mostly. I’ll have to try that in my Wifes Grand Jeep. Should be easy enough to feel the difference between 2nd and 1st.
It’s pretty tricky. We drive 4x4s. It’s not unusual to need to go into low range (not just ‘first’) in deep snow (one foot or more). While this provides a great deal more tourqe to the wheels, and can cause the wheels to break free. Sometimes, it’s the only way to provide enough power to keep the vehicle moving through it without bogging down.
Oh yeah. Also, bad news if you are going uphill on an icy road and the tranny desides it wants a lower gear.
I don’t know about you but in every automatic I’ve ever driven, you put it in D and the car decides when to go to OD, not me. (Unless you push the OD Release button so it doesn’t, which I guess most have now.) In any case I meant overdrive.
Oh, there’s that torque thing again. Downshifting increases torque, but decreases speed.
Volvos for one.
If you place the trans in winter mode (Push the W button) when in position D the car will make a 3rd gear start and then shif to fourth. If you place the shifter position 2 the car will start and stay in 2, if you place the shifter in 1 it will start and stay in 1.
I hate to disagree with Gary T, but I have never seen a trans that will downshift and over rev an engine. In this I include the units I drove when I was young and dumb, and did many a stupid thing. I never had an engine over rev. Nowadays with electronic controls, the electronics won’t let you do something stupid. For example to demonstrate to my students that the control unit really does protect the driver from stupid mistakes, I will place the selector into R when going oh say 50mph forward :eek: Result? nothing, the trans just stays goes to N and stays there.