I admit that this was more of a theoretical proposition, along the lines of “why would you want to do such a thing?” Please note the bolded passage.
Somehow this part seems to have been overlooked.
The original question asked about “drive 2,” not about “2.” The word “drive” implies automatic shifting of two or more gears, not selection of only one gear. If it’s labeled “D2,” I think it’s safe to say it will start in 1st and shift to 2nd. It will not shift higher than that. If it’s labeled “2,” it probably engages only 2nd, though it wouldn’t surprise me if on some cars it starts in 1st and shifts to 2nd.
Just wondering: most new automatic cars in Europe have 5 to 7 gears and sequential shifting. Some cars (Alfa Romeo comes to mind) even have paddles behind the steering wheel. Yet, in this forum I keep hearing about 3 and 4 gear cars. Aren’t those features available in the US yet?
Re: gear D versus OD, my last 4 cars have had gear select indicators for both OD and D.
These cars:
2002 Mercury Sable: OD, D, 1
1996 Chevrolet Caprice Classic: OD, D, 2, 1
1993 Oldsmobile 98: OD, D, can’t remember if it had 2, 1
1992 Mercury Grand Marquis: OD, D, can’t remember what if had below D. I know it had something.
The car before that was a 4-speed stick.
The car before that was a 1977 Ford LTD. It had a 3-speed automatic, so it just had D, 2, and 1.
I know what you’re talking about, though. I suppose if you look back, you could make a list of cars across the years that used the push-button overdrive toggle, explaining the fact that you’ve never seen cars like most of mine.
I had a rental 2002 Ford Escape, and it had a little toggle button to enable or disable overdrive. I also drove a Honda CRV with that feature.
In case you misread, I used the selection of gear 2 to force my Caprice to shift the car UP to 2nd gear from 1st while I was idling it or operating it at speeds under 10 miles per hour. This would prevent it from trying to idle at 9 MPH in D, and keep the wear down on my knee and legs at the McDonald’s drive-thru or similar situations.
All automatic transmission cars with overdrive (= 4th gear) have a way to select drive (automatic shifting) without going into 4th. On some, there’s a choice between “OD” (4-speed drive) and “D” (3-speed drive), others have only “D” and there’s an overdrive-off switch to disable 4th (both types have been mentioned above). Different car makers seem determined to find and use different patterns of gear selection and different ways to indicate same. If you want to know how it’s laid out on your car, check the owner’s manual.
I’ve driven them nearly exclusively in my lifetime, and I quite distinctly remember my dad (who is a Chrysler mechanic in the powertrain components dept) showing me that even if you put it in the lower gear, if you run it to the redline, it will upshift out of your current gear and into a higher one. Iy my current car wasn’t an autostick, I’d go out and try it this afternoon on my lunch break. The autostick, however, is a slightly different computer controlled version of the automatic, and it definitely will shift up if you leave it in one selection till the redline.
One of the reasons for keeping the selector in the lower gear is that if you leave it in “D” and floor it, on some cars, it will upshift before the redline, and when drag racing (on an approved track, etc etc) some people want to go all the way to the redline before the shift.
Hmmm. I may have misread, although another phrase that fed into my interpretation, which I didn’t quote, is “allowed you to spend less time pushing down hard on the brake pedal.” Going into 2nd as opposed to 1st wouldn’t allow to spend less time on the brakes but more. So I assumed you were talking about 2nd as opposed to D.
I suspect you’re thinking of using to 1 to SLOW the car from higher speeds.
I’m trying to refer to using 2 to keep the car from REACHING higher speeds… or any speed at all.
Let’s look at hypothetical car similar to a 1996 Chevy Impala SS with a Gear 1 with a ratio of 3.06 and a Gear 2 with a ratio of 1.63. The calculated torque curve on this engine shows that at an 800 RPM idle it makes in the vicinity of 150 ft-lbs of torque.
After all of the calculations for tire size and gear ratios are completed, the car is capable of providing 1050 ft-lbs of torque to the rear wheels if it were at full throttle, and likely around 250 ft-lbs of torque or so at an idle throttle setting.
At this setting, holding it still using the brakes is a little bit tiring.
With Gear 2 active, you wind up with a full-throttle capacity for 545 ft-lbs at the wheels, and a likely delivery of 136 ft-lbs of torque to the rear wheels at an idle throttle setting.
In Gear 2, I will only have to apply 54% of the braking I would have to have applied in Gear 1 to keep the vehicle stationary.
If I did the numbers for Gears 3 and 4 (which I can’t force that car into at a stop) you’d see even lower torque numbers.
The above calculations assume that the vehicle makes 25% of peak torque at idle. This assumption is based on my readings of certain on-board diagnostics tools on a number of vehicles, but is still a shaky conclusion. However, regardless of the value plugged in where I used 25%, the relative torque numbers would wind up being the same.
Amend
“After all of the calculations for tire size and gear ratios are completed, the car is capable of providing 1050 ft-lbs of torque to the rear wheels if it were at full throttle, and likely around 250 ft-lbs of torque or so at an idle throttle setting.”
to
“After all of the calculations for tire size and gear ratios are completed, in Gear 1 the car is capable of providing 1050 ft-lbs of torque to the rear wheels if it were at full throttle, and likely around 250 ft-lbs of torque or so at an idle throttle setting.”
He never said most Europeans had automatic transmissions, just that of European cars with automatic transmissions, have fancy-pants shifting and gobs of gears.
There are automatic transmission cars in Europe, but the percentage is really low. I guess it is similar to the percentage of stick-shift cars in the US.
This is certainly not the case for all vehicles. I’ve been in both a Pontiac Montana and a Chevrolet Express 2500 that, while moving down the road at 90 (Montana) or 40 (Express) km/h, could be shifted from D into R. In both cases the result was a sudden engine stall (as might be expected), and in both cases the engine restarted when N was selected and the starter engaged. The Montana was of the 2003 model year (give or take) and the Express was a 2005.
Further, I’ve been in a 1984 Chevrolet Cavalier in which it was possible to shift from D to 2, then subsequently to 1 while going about 80 km/h down a steep hill. The result was a very high-speed and noisy revving of the engine until the 2 was again selected.
So maybe it’s just GM, but not all cars are smart enough to keep you from putting the gear selector in the wrong place.
(If anybody’s curious, the Montana was a passenger playing a trick on the driver, the Express was the driver aiming for neutral and overshooting, and the Cavalier was the driver tyring to see if the car would do it. wolfstu does not recommend stalling the engine out at highway speeds; both power brakes and steering become inactive.)
Well not on subies (Subarus). If you hit the redline on a a/t ‘sports shift’, the rev limiter will engage, it will NOT shift you to the next gear. It will however downshift you back to 1st when you slow to a stop (you can start in 2nd if you want, but you must manually put it into 2nd). In ‘sports fully auto’ mode it will take you to redline before shifting under heavy acceleration - but that is fully auto mode. (there is 3 drive modes - normal a/t, sports a/t and sports shift ‘manumatic’).
OK, can I amend my answer to on real cars the computer won’t let you do anything stupid?
(Ducks and runs like hell)
As Gary T said upthread a bit, God forbid that all the car makers do it the same way.
I hope it’s appropriate to ask this question here. It’s closely related, and I’d hate to burden he forum with two threads.
Somehow, our Saturn Ion (2003) gears correctly in hilly and mountainous driving. We can leave it in D, and going downhill, you can “feel” the car holding the gear and not shifting up. It will not shift up until the car has leveled off. I don’t know whether it senses the incline or what. Does anyone know how the car does this?
While waiting for my g/f to finish a doctor’s appointment, I read up the car’s manual (I was bored and forgot a paper or book) If an automatic version, the gearbox’s “2” option would hold it in 2nd gear and 2nd gear only. It also had D1-D4 (Honda Civic) that would do the same with other gears and it was also suggested the car could be driven as a semi-automatic simply by pushing up and down through D1-D4. This “semi-automatic” mode IIRC was frowned upon by other Dopers in a thread quite some time ago.
IMO most cars in Europe would have smaller engines and be designed with frugality in mind. More gears mean more economy and are handy for squeezing more performance out of the engine. If you have a large V6 or V8 and have cheap fuel, you don’t have to worry so much about how many gears you have. All the same, I would have thought more than 5 automatic gears would still have been the preserve of more expensive motors.
If I am understanding you correctly, Volvo did that for a few years back in the early 90s. When going downhill, and the trans was set in ecomony mode if the trans control unit saw the speed increasing, it downshifted to 3rd to allow engine braking. This was done to help make the brake pads last longer.
Customers did not understand the function, complained, and it was removed a few years later.
Yes there is a stall converter which would stop the engine if the tranny speed and engine speed were too far apart for too long. In one shop manual I had (forgot which car) it gave a way to test the stall converter. IIRC it was to block all wheels, set the E-brake fully, fully apply the service brake, and place the car so that forward movement would not cause harm (like a big empty field, or the front bumper up against a old growth oak tree. Then place the selector in 1 and, well basically floor it till a certain rpm’s were reached and hold it there for a certain amount of time, the engine should stall out if the stall converter was working.
