Like most (all?) people, I put my car in “D” and go about my driving business. But next to the big D, there’s a “3 2 1”. Are there any good situations to use them? I can kind of (maybe) see the usefulness of first gear but the other two just seem completely unnecessary.
When going downhill for an extended period of time you can put the car into a lower gear to slow you down so you don’t ride the brakes.
One situation where you might want to lock the car in a particular gear is driving in icy conditions. You don’t want the car changing down while going around a sharp corner, as the increase in torque can cause the wheels to break traction. This actually happened to my driving instructor once, it changed down to first and he had a very slow speed collision with a hedge.
I use my 3 gear to while towing. Using D can burn out your overdrive.
while that may have been the case in the early days of 4-speed transmissions, the reason nowadays is because overdrive can drop the engine too low in its powerband for towing anything effectively.
My Chevy truck has a towing mode button on the gear shift although I don’t think I’ve ever used it. How is that different than putting it in 3?
When driving in hilly areas I tend to manually downshift one gear since it’s easier to maintain a constant speed. As already noted it provides engine breaking going downhill. Going uphill the car would eventually downshift itself, but usually loses speed first before it reacts. This is the most common scenerio, going from Overdrive (4) to (3), so often there’s a button you can just push to save you the trouble of moving a big lever…
(2) and (1) are generally less useful, except for for some situations off-roading in a 4wd vehicle, (Though I could maybe see (2) for engine braking on very steep roads). My Jeep Grand Cherokee has them being off-road capable but some vehicles omit them (like my sisters Toyota Corolla).
In addition 4 wheel drive vehicles have a shifter for the transfer case, for my full time 4WD its [Hi] for normal driving [Neutral] to disengage for being towed, and [Lo] for when you need a lot of power as opposed to speed, say extreme off-roading or pulling a boat out of a lake.
Back in the '80’s and '90’s, my dad took us on summer vacations to the western US in a station wagon towing a pop-up camper. Some of these station wagons (he went through several over the decades) had overdrive on them. In cruise control on a level highway everything was fine, the transmission stayed in top gear. But if we came to a significant hill, the speed dropped and the cruise control put the throttle down enough to make the transmission downshift. With the extra torque at the wheels, the speed climbed back up, the cruise control eased up on the throttle, and the transmission upshifted - and then the decel-downshift-accel-upshift cycle would repeat until we crested the hill. The solution was to wait until the first automatic downshift as the climb began, and then move the PRND321 selector down a notch to hold it in that lower gear until cresting the hill. For even slower ascents on very steep mountain grades, you could just as easily select a lower gear - 1 or 2, depending on the grade and twistiness of the road. If you’ve never been to the mountainous areas of the western US - especially away from major interstate highways - the roads can be graded pretty steeply, and there are often switchbacks and squiggles that necessitate a very low speed.
If we were going to descend a long mountain grade, letting the transmission stay in overdrive would allow the whole rig to build up a lot of speed, requiring heavy braking to keep it within reason. Solution: when cresting the grade, if a long, steep descent was awaiting us, we’d leave the PRNDL321 selector in the lower position that we had chosen for the climb. You still needed some braking, but not nearly as much as if the transmission were in top gear.
Most small, lightweight cars won’t be towing much of anything, but if they’ve got a low power-to-weight ratio and/or if they’re carrying a full load of people and cargo, they’ll still struggle to climb mountain roads. Not only are those roads steep as described, but you’re also at high altitude, typically above 5,000 feet in the Rockies, and the thin air up there robs the engine of a significant fraction of its output. So even though you’re not dragging a trailer behind you, you may still want to force a lower gear to prevent the transmission from constantly upshifting-downshifting-upshifting-downshifting.
Exactly what Machine Elf said. Flatlanders just don’t get that you can have several miles of 7% grade, followed by a mile or so of 9%. Brakes are sized and designed to provide several full speed stops. They are not sized to control speed down multiple miles of mountain grade.
I’ve also used 1 and 2 for very slow driving in terrible ice/snow/slush conditions, where I wanted to drive 5 miles per hour without having to ride the brake.
I’ve always wondered how this works.
I drive a stick. When I’m in really slick or snowy conditions, I may start from a standstill in 2nd gear instead of first, so as not to be as likely to spin my tires. Now, in an auto “1” and “2” will limit the gear selection to first gear, and to first and second gear, respectively, right? When you’re driving 5 miles per hour, why would an auto be outside of 1st gear? “2” doesn’t mean second gear, does it? It means first and second, no? So when you’re at 5 mph, why would you be riding the brakes? Surely, the auto isn’t past first gear at that speed, is it? At worst, I guess it might be on second, but I personally can’t remember any autos I’ve driven where 5 mph would be anything but first gear.
Sometimes my car won’t start out in first gear when the transmission is in D. I have to manually shift into first, get up to speed, then shift to D.
I realize that’s a problem with my car somewhere and not a normal thing.
If your brakes go out, you can gradually downshift to lessen your speed (somewhat) before you crash into something.
All I know is if you have your foot off the gas in D you go forward faster than you do when you have your foot off the gas in 1.
This is interesting. Why would this be the case? I’ve personally never noticed this in my autos, but the last time I owned an auto was 20 years ago, so maybe things have changed.
Tow/Haul mode doesn’t keep you out of overdrive. It just adjusts when the transmission shifts. Usually it will delay the shift when climbing a grade to allow higher rpms before shifting, and shift earlier allowing more drag from the engine and transmission when descending. At least that appears to be what my dodge does.
In some cars ‘2’ will stay in 2 and not vary between 1 and 2. This allows you to start driving in second instead of first, useful on slippery conditions where 1 would spin the wheels.
Not to be rude, but if you’re asking this question then in a sense the answer is no - there are no good situations where you would use them.
There are umpteen reasons why a good driver would want to use them. These can be broken down into either car handling reasons where you would not want the car to suddenly upshift (or downshift if it were in a higher gear) (which in the worst cases could cause an instant spin if the car were near the limit of adhesion) or roadcraft reasons where as a driver more intelligent than the gearbox you either want the engine in a different part of its powerband (e.g. you anticipate overtaking someone soon, which if you’re doing it properly you don’t want to be just relying on kickdown) or you want increased engine braking (such as the hills example). If your gearbox is crap then there is a reason 2.5 , you want to stop it from hunting.
If you are interested in being a good road driver, although it is a British book it is still the one to start with - Roadcraft: The Police Driver’s Handbook. It teaches a system to use in all aspects of driving that is the foundation of pretty much all advanced driving groups I am aware of.
That’s interesting. The automatics I’ve had didn’t work this way, but that would make sense to start in 2 in slippery conditions if the transmission locks into second gear and skips over first. What doesn’t make sense is why “D” would accelerate faster than “1” with the foot off the brake, as in Lemur’s case. Wouldn’t both transmissions be in first in that case? Why would riding the brake in “D” cause the car to go faster than riding it in “1”? I could believe it’s some quirk of autos, but I’d be interested in hearing what’s going on to make this the case.
Not into the whole fighting ignorance thing, are you?