Can we use Neutral (N on the selector) instead of Park (P) when parking on a flat surface?
Is this useful for transmission system? Because every time we put gear on P we must pass through R and will this reduce gearbox/clutch's life?
What is the mechanical difference between Park and Neutral? I think Park is basically neutral, but with a parking pin locks the wheels from moving... so when surface is flat we don't need that pin and using handbrake is enough.
What do you think?
Depends on the car.. some won't let you remove the key from ignition if it's not in park.
To be honest I really wouldn't worry about "crossing" reverse when heading for Park there is usually a slight delay before it engages the clutch anyway so when moving the selector you will be past it and into park before it does anything about selecting reverse.
"Park" is, as the name implies what it's designed to be put in when parking up so it's a safe bet that that's a good course of action.
The simple answer is "No". There is no useful reason/benefit to using the transmission any other way than it was designed.
Use PARK (P).
Can we use Neutral (N on the selector) instead of Park (P) when parking on a flat surface?
Possibly. Others have delved into the details already, read the other answers.
However there is one important point that I have not seen brought up yet.
Regardless of the type of transmission, you should have two mechanisms stopping your car from moving while unattended. With an automatic transmission, put the gear selector in Park, and engage the parking brake. With a manual transmission, put the gear selector in first gear (or reverse, whichever is recommended in the owner's manual) and engage the parking brake.
The goal here is to have a failsafe: systems can and do fail. Let us say you park in neutral and engage the parking brake. Now if someone cuts the physical cable (parking brake works like a bicycle brake with a steel cable to engage the brakes, and usually only the rear ones) they can roll your car away to a chop shop1, roll it into another car for "fun," whatever they want while you are not around.
What if you use only the parking gear but not the parking brake? While rare, transmissions do fail. What if the parts responsible for stopping the transmission from moving cracked and broke? Your car could roll away due to gravity or thieves. Note that even a "flat surface" does not mean "level" and what appears level might not be.
By using both mechanisms together, you mitigate the risk of your vehicle moving without you intending it to. Both systems have to fail, and at roughly the same time.
There is a third mechanism for use on hills, which is actually coded into law in some jurisdictions: curbing your car's wheels.
What is the mechanical difference between Park and Neutral?
Park engages a parking pawl inside the transmission which prevents the transmission output shaft or shafts from moving more than a tiny bit (the little bit of give is why a car might lurch a few inches after parking on an incline). Other than that, park might be equivalent to neutral, or there could be another locking mechanism. Any differences are specific to the manufacturer and model of transmission.
1 There are ways to steer cars even without the key, such as when the manufacturer does not put a steering lock in the car to begin with.
Setting your car in Park does not cause wear of any kind, and most automatics I have driven will not start or let you remove the key in any other position than Park.
First of all, I'd like to point out that even if Reverse did fully engage, the wear on clutches and brake bands caused by it is about the same as each of the individual gear shifts your transmission made during your drive. You should not worry about how many times your transmission changes gears. Very heavy loads and aggressive driving are the real causes of increased wear on an automatic transmission.
Now, putting your vehicle in park will not cause any wear, because:
In a computer-controlled automatic transmission, the computer will only change gear if you stay in the gear for a while. Moving from Drive to Park, even relatively slowly, will not cause the transmission to even consider engaging Reverse.
On a fully hydraulic automatic transmission, Reverse will be engaged immediately, but this operation is so slow that if you move straight from Drive to Park in a direct motion, it simply won't have time to do anything, much less cause wear.
If the vehicle is turned off first, all gears will be stationary, so even if you fully engaged Reverse, there will be no wear on the clutches and brake bands of any kind.
The parking prawl and parking gear are quite massive chunks of steel, and their only wear is mild friction when engaging. Nothing short of intentional destructive behavior will cause noticeable wear on your parking prawl and gear.
I would also like to add that having a habit where you do not always engage park is probably a bad idea, as you risk forgetting to engage park when you really need to, instead of it being plain muscle memory. Even a well-serviced handbrake is much less capable than a parking gear, and handbrakes in automatics are usually far from well serviced (even if they're used, their reduced effectiveness is hidden by the parking gear).
Others add that engaging the handbrake prior to the parking gear may be a good idea in order to slightly reduce wear on parking gear and prawl, and ease parking gear disengagement (which can be hard when the parking gear is engaged in a vehicle on a slope). The parking gear does not engage unless the vehicle moves slightly after being put in park, so in this configuration, it will only engage if the handbrake slips. I do not do this myself, as I see no reason to worry about parking prawl/gear wear, and would rather have certainty that the vehicle cannot move.
Because of the way an automatic transmission works, this really is a non-issue. You're probably thinking about how in a manual transmission, when you move the gear shifter, you are physically pushing and pulling different gears into place.
In an automatic transmission, it does the work for you using hydraulic pressure. When you move the gear selector, you're only opening certain fluid valves (or signaling the computer to do this), and it takes a (short) bit of time for the gears to actually move and change. If you move the selector quickly past reverse, the gears don't really have time to react. With an electronically controlled transmission, chances are nothing happens at all if you don't pause on reverse.
Also as motosubatsu mentioned, you can't remove the key unless the car is in park. This isn't something that manufactures just decided to do, it's actually a federal regulation covering vehicle safety that specifies that the key can only be removed in park to prevent rollaway and theft.
Leaving car in neutral can be quite dangerous, if someone rest on your car and your car don't have hand brake engaged your car will start moving and can hit another car, get on the road or hit somebody. Gears and clutch wear when there is extreme force or heat caused by friction, which means putting car in park won't cause any damage, as long, as the car isn't moving and it's recommended to put it in park.
A bit off-topic but also don't engage your car hand brake in winter because, it will freeze and can damage the hand brake cables or pads will stuck to the rotor.
The difference between neutral and park in your auto transmission is that the auto transmission has something called a parking prawl which basically physically locks your transmission gears.
https://estimate.myautomatictransmission.com/transmission-parking-pawl/
You need to put the transmission in park else the car will roll away. Even on a flat surface this is a concern because someone can just push your car out of the way.
While on the topic, you should take special care when parking on a steep hill. Do not just put it in park. This would result in high pressures on the parking prawl which will make it hard to take the tranny out of park -- because the force of the prawl holding the car on that hill. Instead, engage your parking brake and let the car rest on that, and then put it in park.
Aside from making it easier to take out of park, you also minimize the risk that using the parking prawl to support the weight of your car on a hill for extended period might physically brake the prawl.
UPDATED: In the part of the answer speaking of using the e-brake first when parking on a hill, with the regular brake applied you engage the e-brake and still in drive, then let your foot off the regular brake. This sets the weight of the car on the e-brake. Then you engage the transmission in park. You end up with both the e-brake and parking prawl together holding the car on the hill, but the majority of the force is on the e-brake.
Compared to non-automatic transmissions, the Neutral gear is like separating the transmission (no gear at all), whilst Park is connected transmission (usually you chose the first gear on non-automatic transmissions). With the transmission separated, the car will roll away if the ground is not perfectly flat (and be sure, there is hardly any perfectly flat ground).
Some cars have a security function that prevents the key from being pulled out if the Parking gear is not set - to prevent you from mistakenly letting your car roll away.
TLDR: won't make a difference. But other driving techniques will. Pursue those.
It won't reduce wear and tear. Automatic transmission wear does not work that way.
Wear in an automatic happens when clutches and bands are engaged whilst the surfaces are spinning in opposition, i.e. When shifting gears while underway. Wear and tear does not occur in the torque converter. What happens instead is heating of the hydraulic fluid, which is why there's an extra radiator inside or in front of your regular radiator to cool your transmission fluid.
If your engine is at idle, there is little wear engaging either R or D gears: at idle, the torque converter output shaft is barely moving with little force behind it, and the car is stopped, hence the engaging surfaces are barely moving against each other and they engage trivially.
In any case, the reverse gear takes a second or so to engage (and on computer controlled automatics, longer than that, as they seek to discourage people from trying to rock cars out of ruts). Simply passing through the gear briskly from D to P doesn't give the clutches/bands time to engage, and in a computer controlled transmission, the computer will decline to engage them regardless, since it sees the handle is actively in transition.
If you are keen on reducing wear, try reducing the power level at which the transmission shifts. For instance I got to know my transmission pretty well, and I knew when it was going to upshift at this throttle setting, so I'd lift off the throttle pretty much at that moment, - this input also caused the upshift, since it was defering upshift because I was on power. After the upshift, I'd reapply power, but not so much power as to make it downshift again. And of course good driving planning so I don't often have the heavy jab of power that causes a downshift, because that is the worst case scenario for clutch/band wear.
Question seems still not clearly replied. I found this topic while searching for something similar.
Question is clear. Let's sum it. Can we use N on a flat surface with hand brake?
So no rolling at all. Not asking about extreme cold can freeze handbrake. Not asking about how he should park. Not discussing over if somebody pushes the car etc. Nearly all replied just to reply.
So let's extend the worry of the question owner. What if another car will hit or push the parking car in P postion? Or a tow operator who will forcibly drag it?
Still no damage at all?
It depends on the condition of stopping. If you are stopping while having the engine running (if you're heating the engine in the morning or when you stop at traffic light or waiting for someone), it's better to put it in Neutral with handbrake on to allow the Automatic Gear Oil to circulate properly. But if you are stopping for parking, it's better to put the gear on "Park", unless you are parking parallel on flat surface that someone might need to move your car while you're away (this is common in my country, indonesia). But again, for safety reason, i think we should avoid parking on Neutral Gear as much as possible as someone might push/move/hit our car while we park and cause the car to roll and hit someone/something (There's a lot of incidents of that in Indonesia). For several brand, you do need to put the gear into Park so you can turn off the engine properly/lock the door, but usually there's a mechanism you can park in "Neutral" (using the lock on gear or for example in my car, i have to put my carkey into a tiny lock hole next to the gear stick to shift the gear from Park to Neutral after the engine is turned off, otherwise it won't let me lock the car
Very bad idea for safety reasons. The best and safest method is to place the transmission in park and set the parking brake. When shifting into drive the transmission will not engage the clutches passing over reverse. Even manual transmission cars need to be left in gear with the parking brake applied when parked. You are putting yourself and others at risk if you rely only on a parking brake.
You dont have to use P especially when parking on flat surface.
Minimizing shifts from N to R then to P and vice versa will minimize wears on clucth packs and brake bands
