Understanding the automatic transmission...
 

I understand what Park, Neutral, Reverse and D4 are, but what's D3, 1 and 2 for on an automatic trans.? What about that little keyhole for "Shift Interlock"?

Pardon my ignorance but where I live when I was taught to drive a couple of years ago I was told to put it on D4 and just drive it. I wasn't told what the other gears were for.

Automatic transmission - Wikipedia, the free encyclopedia

That gives a somewhat clear explanation but I don't know how much of that pertains to Honda's specifically. For example, it says driving in 1 or 2 gear ratios can cause damage at a certain RPM range.

Why shouldn't I use anything but D4? Why is it even there? I'm assuming it's supposed to be used? Am I supposed to move the shifter from D4 to 1 or 2 or D3 while the car is rolling? The thought of that is kind of unnerving, reminds me of moving from D4 to P while rolling. I just never touch the selector while the car is rolling. How am I supposed to use this thing? :confused: Is it like a manual where when I watch videos they start out at 1 and move up gears gradually as they increase in speed?

Just put in D4 and drive. Only reason ever to use a specific lower gear position is possible use on soft ground, or should the transmission fail to respond to D4.

Honda's automatic is reportedly very similar to a manual transmission w/ automatic shifting (hydraulic) and clutches to smooth the shift points.

good luck

D3 will keep the transmission to go into overdrive, if there's alot of hills where you are and you're not driving fast let say 40mph, then keep it in D3 for more power so the transmission doesn't keep going in and out of O.D and lockup all the time, as this will cause the tranny to run very hot which isn't good for it. 1st and 2nd is there just incase you're carrying a trailer of fully load and going up supper steep hill. Most of the time normal driving D4 is good especially MPG. Try NOT doing 80mph and shift into 1st or 2nds or Park, bad things can happen. Key slot for shifter interlock is only needed when you cannot get the shifter out of park then you will have to do it manually by insert the key into the slot and move it.

Transmission has 4 forward gears.

"D4" will use them all, automatically selecting the one it wants. For 99% of the time, that's what you want.

"D3" will use only 1st 2nd & 3rd. It will not use 4th. Some people say that's good for a trailer, but I don't know. It can also be used for some engine-braking when driving down a LONG LONG downhill.

"2" will lock it into 2nd gear. It will not use 1st, even when you start from a standstill. This can make it easier to start on snow or ice. Physics of slippery surfaces still rule, so this isn't magic.

"1" will lock it into 1st gear. Can't think of a real good example of where this would be useful. Maybe driving down a real steep hill jeep-fashion (walking-speed or slower).

You can shift from D4 to D3 to 2 to 1 while driving. But each step of the way you get more engine-braking and maybe a sudden jolt when it shifts. Not recommended as a "normal" way to drive. But it'll help you stop if your brakes fail.