The automatic transmission car is parked on a steep slope, why do you find it very difficult to get

Many people will have the experience of parking their car on a very steep slope, putting it in P gear and turning it off. When the car is started again, it feels particularly laborious to pick up the P gear, occasionally accompanied by a metallic impact sound, and sometimes even a trigger. Why is that?

This starts with the locking principle of the automatic transmission's P gear. The following picture is the structure of the automatic transmission P gear. It can be seen that when the gearbox is hung into the P gear, the parking pawl (hook) and the parking gear (the wheel with a card groove on the outer edge) are meshed with each other, the output shaft of the gearbox is locked, and then the wheel connected with the output shaft is locked, so as to achieve the purpose of locking the car.

When the vehicle is parked on the slope, if the hand brake is not tightened and the foot brake pedal is released, the force of the vehicle sliding down is concentrated on the parking gear and pawl of the gearbox, and the parking gear and pawl will mesh very tightly, not easy to be separated, and the performance is that the P gear is not easy to take off. The solution is to get out of the car and push the car back and forth a few times, and then the P gear is easy to take off.

The way to avoid this is to press the brakes when stopping, wait for the car to come to a complete stop, then apply the parking brake, then push into P gear, and finally lift the brake pedal and turn off the car. This parking method mainly relies on the parking brake system to lock the car, and the P gear is only used as an auxiliary method, and even the gears of the P gear do not need to be engaged.

Now more and more automatic transmissions are using the electronic gear lever, when the gear lever is pulled, it only sends an electrical signal to the gearbox computer, and the computer controls the opening of the P gear locking solenoid valve, so the phenomenon that the P gear cannot be pulled is becoming more and more rare.

Because the forces are concentrated on the gearbox's parking gears and pawls when going uphill, the parking gears and pawls mesh tightly and are not easily separated.

The car with automatic transmission is parked on a steep slope, why does it feel particularly difficult to get from P to D? Lao Hou Xie Che 2018 07 19 21:11 Many people will have this experience: park their cars on a very steep slope.

Because the automatic car is parked on a steep slope, his car will shift on its own, so it will be very difficult for you to change it manually.

This is because when your car is parked on a steep slope, all the parts on it are locked, so it is very difficult to gear up.

Cars parked on steep slopes will have some protection, and changing gears is difficult.

Because the car is parked on a steep slope, it will be subject to some resistance, so it will be very difficult to get into gear.

When going uphill, there is a lot of resistance, so it will be very strenuous.

Because the P gear is hung to D, although the speed has come up, the power is relatively not enough to go uphill.

Because the parking gear and pawl mesh so tightly, they are not easily separated.

Because of this situation, the parking gear and pawl will mesh very tightly.

Because after parking on a steep slope, the vehicle has an inertia that slides downward, which makes the locking mechanism of the gearbox P gear stressed, so it takes a relatively large force to disconnect the locking mechanism when it is hung from P to D, and it will feel laborious.

The automatic transmission stops on the slope and starts to hang D gear, because you directly hang the P gear when parking, the gearbox is locked, and the car should be stopped when parking on a steep slope, and then the P gear will not appear to be the problem of hanging D gear.

In fact, when the automatic transmission is in D gear, it is weak to climb hills. On top of that, as the speed increases, the transmission is also upshifting normally, which is not good news for the owner. The transmission upshifts, the gear is higher, the transmission transmission ratio is naturally small, and the vehicle is unable to climb normally.

You drive in manual mode, choosing 4th gear. At this point, you get stuck in traffic and you start to slow down. Then the gearbox will also automatically downshift.

If we go down to 2nd gear and the engine revs 1000, we move slowly with the traffic. At this time, even if we push the gear lever, the gearbox will not go up 3rd gear. In order to limit the vehicle's ability to climb hills, the owner can selectively use the manual mode to drive the vehicle and manually control the transmission to be in the most suitable gear to ensure the power of the vehicle.

For example, there is a large ramp in front and you can easily ascend with 4 gears. Halfway through 5th gear is underpowered and needs to be downshifted. Then before going uphill, we used the manual mode to limit the gears to 4th gear, so that the engine revs high, and the whole climbing process is full of power, and the speed is stable, and it is done all at once.

The root cause of weak acceleration of the vehicle is that the engine displacement is too low, the torque is too small, the vehicle weight is too heavy, and the driving resistance is too great. The above-mentioned improvement methods can only increase the power relatively, but cannot fundamentally solve the problem of insufficient vehicle power.

Things changed when we went uphill in 5th gear. At the same speed, the engine speed corresponding to the 5th gear is lower, and the power is definitely not as good as the 4th gear. In this way, when climbing halfway, the power decays, the speed decreases, and the gearbox downshifts.

During downshifting, there must be a period of lack of power, so even if you shift to 4th gear, it is not as fast as climbing directly in 4th gear at high speed. So you will feel a lack of motivation. Whether it's a dual clutch or a dual clutch, a car with a normal automatic transmission defaults to the lowest gear when you're in gear uphill, and the CVT, even if it's a manual automatic, can also be a transmission slippage, resulting in a lack of power delivery.

If we switch to manual mode when going uphill, most transmissions will automatically drop one gear. At this point, depending on the slope, decide whether to continue lowering the gear. If the slope is large and the distance is long, you can also lower two gears in advance, increase the throttle, and increase the uphill speed.

At this point, the motivation does not feel weak. Of course, the same goes for switching to sport mode. Or press the throttle before going uphill, and the gearbox will automatically downshift, and the uphill will be calmer.

with sport mode.

Sport mode is referred to as sport mode, in which the engine torque can be output quickly in the shortest possible time, and the engine torque value is very large, which naturally leads to the increase in vehicle power. Especially when accelerating from the start, the vehicle will clearly feel the feeling of pushing back, and the engine speed will rise more rapidly.

The D gear of the automatic transmission is a relatively intelligent automatic shift driving mode, his upshift is mostly about 2000 rpm as an opportunity, many even lower than 2000 rpm on the automatic upshift, the purpose is to ensure better fuel economy, and this is prone to high-end and low-speed situations on the uphill road.

Automatic transmission car needs to use D gear when climbing, push D gear forward to become the 2nd gear of manual transmission, the car first needs to tighten the handbrake when going uphill, and then start the car with the right foot when starting, and hang the gear in 1st or 2nd gear to start driving. The P gear in the automatic transmission is called the parking gear and is used to stop the car. The working principle is to use a mechanical device to lock the rotating part of the car so that the car can no longer move.

When the car needs to be fixed in a certain position, it should be in the P gear. The R gear is the reverse gear, which is used when reversing. When the vehicle is not completely stopped, you should not use the R gear at will, otherwise the transmission will be damaged.

N is neutral and is used to start or wait for a traffic light. D gear is the forward gear, which is used to drive on general roads. The D-gear is characterized by forced resistance, which is conducive to high-speed overtaking.

Quickly pedal to the end while driving, and the force block switch will be turned on, so you can quickly increase your speed.

Automatic transmission uphill can generally be hung to D gear, some cars will have D-1, D-2 gear, which is specially designed for going up steep slopes. Automatic transmission models in the uphill start, with the foot on the brakes, try not to count on the handbrake, sometimes the handbrake can not be pulled to the end, easy to slip the situation, compared to the manual transmission uphill start needs the handbrake to cooperate, automatic transmission in the uphill start, or step on the brake to hang the low gear and then start better; When the vehicle is at the bottom of the slope, the climbing gear can be hung when the engine is turned off and ready to climb. The D gear of the automatic transmission is a relatively intelligent automatic shift driving mode, his upshift is mostly about 2000 rpm as an opportunity, many even lower than 2000 rpm on the automatic upshift, the purpose is to ensure better fuel economy, and this is prone to high-end and low-speed situations on the uphill road.

Automatic parking climbs are weaker, mainly those naturally aspirated cars with small displacements. Naturally aspirated engines have no advantage in torque, and torque release at low speeds is even less ideal; According to the power = (torque x speed) 9550, it can be known that the naturally aspirated engine does not release the torque well at low speed, so the power released at low speed is not enough, and it is difficult to climb naturally; For automatic transmission vehicles, the inability to climb in D gear is only relative, and it does not mean that D gear cannot climb or fail to climb. It's just that there is no usual power for climbing, and there is no usual power even when the throttle is pressed deeply.

Actually, this is normal! When the vehicle is going uphill, the resistance is much greater than usual. It's like when we ride a bicycle uphill, we not only have to exert several times as much effort but also slow down.

In fact, the automatic transmission can't go uphill when it's in D gear. On top of that, as the speed increases, the transmission is also upshifting normally, which is not good news for car owners. When the transmission is upshifted, the gear is higher, and the transmission ratio of the transmission is naturally smaller, and the vehicle cannot climb normally.

You drive in manual mode, choosing 4th gear.

At this point, you start to slow down in a traffic jam. Then the gearbox automatically downshifts. If we go down to 2nd gear and the engine revs 1000, we will move slowly with the traffic.

At this point, even if we push the gear lever, the gearbox will not upshift 3rd gear. In order to limit the inability of the vehicle to climb hills, the owner can selectively use the manual mode to drive the vehicle, manually control the transmission in the most suitable gear, and ensure the power of the vehicle. Many people buy automatic cars, often in D gear, which are used in urban areas and highways, and even when going uphill.

For a car with plenty of power and an intelligent gearbox, D-gear is no problem. Even when climbing hills, the gearbox intelligently and automatically selects the appropriate gear according to the load on the engine. But many cars just have enough power, and the gearbox is just an ordinary gearbox, which is not smart enough.

If you can't climb a long steep hill in D gear, how do you shift gears? Let's start with the automatic transmission car going uphill. For most road conditions, it is good to use D gear, which has a wide range of use.

For some common ramps, there is basically no problem with block D, so don't worry too much about this. If there is a lack of power when going uphill, you can appropriately increase the depth of the accelerator, and the power performance will be better.

It may be caused by a mismatch in gears, or it may be caused by a lack of oil, and there are many reasons for this situation.

I think it should be your wrong gear, automatic cars should choose S gear when climbing, compared to D gear, S gear will be stronger, for some longer slopes or steeper slopes using S gear will have better results.

It may be that you have chosen the wrong gear, you should choose S gear or L gear, which is more suitable for climbing at this time.

It is difficult to put the automatic car in gear, there is a problem with the gear, check whether the car is in the gear is leaking whether there is a rotten smell, and the reasons for the sound of the gear are improper operation, clutch failure, sprocket wear, and loose chain.

On the issue of abnormal noise of the car, it is difficult for ordinary car owners to distinguish which is louder and which is reasonable. Only nearly 20% of the vehicles that went to the repair shop to detect abnormal noises really had problems. In the case of a turbocharged engine, there is a must be a difference between the sound and the sound of a naturally aspirated engine; Models with engine guards may also make noises due to friction; After some car owners come into contact with different cars, it is likely that they lack their own understanding of mechanical knowledge, so they can distinguish the abnormal noise of the car and avoid wasting time and energy.

Second, the identification method of car noise:

In practice, due to the limitations of working conditions, it is difficult to measure the sound of the car with special instruments, and the sound of the car can only be described and compared with the judgment of the sound in daily life. For example, the "rattle" sound caused by the dry friction of the bearing, and the "click" sound similar to the small hammer hitting the cement floor caused by the excessive valve clearance.

1. Correctly distinguish between normal and abnormal sounds.

The vibration of each mechanism in the work of the car will emit a variety of sounds, but the sound does not mean that the car is faulty, in order to avoid unnecessary disassembly, we must first distinguish between normal sound and abnormal noise. The normal vibration sound of each system component (such as the noise on the surface of the engine), the impact sound of the gear when shifting, the air intake sound and exhaust sound of using gas as the working source, and the gear meshing noise are all normal sounds. Abnormal noises, mild noises, normal sounds, and malignant sounds.

Slight noise, such as the flashover sound of high-voltage electric leakage, the slight loose sound of rolling bearings, etc., the general volume is small, the degree of wear of the parts is not large, and there is no significant change for a long time, and this kind of fault can still maintain the normal operation of the car without repair.

3. When diagnosing abnormal noise, attention should be paid to creating good auscultation conditions and trying to eliminate the interference of other noises, so as not to affect the accuracy of judgment.

It is best to consciously amplify or reduce the sound, that is, use a screw or other metal rod as a stestological instrument to contact the sound part to amplify the sound, or use a single cylinder fire cut-off to reduce the sound to meet the diagnostic needs. The auscultation site should be kept quiet to minimize human interference.