Introduction to Must-Not's on Automatic Transmission
Ok, I get on my friends' car often and most of time, I take the shotgun. Unfortunately, there are many things that go wrong in terms of driving habits. And such bad habits are formed from wrong advice and misconception. So I decided to point that out here today.
Hope you find it useful!
1. Never set in Neutral when coasting down hill
There are three main reasons to this.
a) Unlike common misbelief, you won't be saving more fuel compared to just releasing your feet from the throttle
Most of modern cars cut fuel injection to the engine when driving downhill. Rotation of your wheels is used instead in powering the engine. If you check your fuel economy reader while coasting down, you'll realize that it's highest at the point.
b) You lose control when you set in Neutral
You can always come across a situation where you need to speed up. If you set in N, you give away the power to speed up in certain emergency situation. Sometime, you need to accelerate to avoid accident.
c) It's illegal in many location.
Many states in US including California and Georgia, it is illegal to put on N while coasting. Whether you live in the US or not, this might be the case for your area as well. Why risk it?
2. Come to a complete stop when shifting N->D or D->N
You have a part in your engine called "automatic transmission band" that is housing the gears. It clamps down the gears to completely lock the transmission. So when you are shifting gears while in motion, the band is going to clamp but fails to lock, hence unavoidable slips. While the slipping occurs as it tries to squeeze rotating gears, that's when damage is done on the band.
The band itself might not cost much but it requires digging deep to replace it. So, the whole repair cost is not minuscule at all! Unless, you are going to do it..
3. Don't launch your vehicle
For the sake of longevity of your car, it is highly recommend it not to launch in any case.
But, for those who are like me, who never really listens, if you are going to do it, never rev up at N and shift to D when launching. As explained previously in #2, this practice damages the housing band costing you quite a bit to replace it.
Instead, press on the brakes and rev up and release the brake as you launch. This is better for your car but again, don't launch unless necessary.
4. Don't place at N when waiting in the red traffic light
Myth 1) If you are on D and pressing on the brakes, you are putting too much strain on transmission.
False accusation! Accelerating from complete stop, which we always do, gives much more pressure on the transmission in the first place. Therefore, merely braking while on D is insignificant.
Myth 2) You can save fuel economy.
Not quite! For instance, on my mom's car, Volvo, on the live reader, the fuel consumption is 0.3 gallon/hr when waiting in the red light on D. This means, the 30 seconds of waiting cost me about 0.00025 gallons. Ok, is that amount of ant's urine? If it pisses at all, that is.
If you are stuck in a long traffic not moving at all and really want to save on gas, turn your engine off. That way you can literally save by not spending at all!
Otherwise, there isn't much benefit of putting it on N.
5. Put it in Park while your vehicle is moving. NOT! Don't do it!!
When you are in park, there is a locking pin that complete holds the transmission in motion. So if you abruptly set on P while your car is still moving you are eventually going to break it.
Now, you might go, "what if I'm in emergency where I have to stop?"
Honestly, I can't think of a situation where you feel the urge to do this but say, your throttle is stuck for some reason and your car is keep accelerating. Make sure you firmly press on the brake pedal so that vacuum assist is fully engaged. Second, downshift which is actually going to speed down the car.
Aight, that's sums up today's topic. Protect your car AND YOURSELF.
On to the next one!
One Take Away
There isn't many cases where you have to put on N for you automatic transmission vehicle. If not, ANY. Maybe only when the car needs to be pushed manually :)