The gearbox of a car, like the engine, is an oversized part of the car, and the cost can account for 15-30% of the whole car price. Generally, there will be no fault in the gearbox, but a fault is a big trouble. Today, we selected ten common faults of automobile gearbox and analyzed them one by one to share with you.
Common fault 1: oil leakage
Fault analysis:There is oil oozing from the gearbox housing or oil pan, one reason is that the seal is aging and the seal is poor; Another reason is that the shell has trachoma caused by poor manufacturing process.
Common faults 2: delayed entry, impact and engine flameout.
Fault analysis:The normal standard for entering the gear is to feel entering the gear within 1-1.2 seconds. When the brake pedal is released, the vehicle will slowly start without stepping on the accelerator pedal and gradually extract the speed of 10-20km/h..
If it is more than 2 seconds after entering the file, locate the delay of entering the file. This situation needs immediate repair.
If there is a strong impact feeling when entering the gear, the impact will be positioned.It should be noted that any automatic gearbox has a certain degree of impact when it enters the gear.If there is no feeling at all, it means that there is an internal fault. However, this shock is unacceptable, and the causes of this fault phenomenon are very complicated, including many aspects except gearbox.
The situation of dead fire when entering the gear is that the engine will die when entering the gear. This problem is more obvious when the car is cold. This problem is caused by gearbox problems and other body systems.
Common fault 3: hang in D or R, and the engine is turned off.
Fault analysis:This failure may be caused by the damage of the locking solenoid valve or the card issue of the locking control valve.
After shifting into D or R gear and releasing the brake, the vehicle does not move. Or the car can travel a short distance after the cold car starts, but it can’t travel in the hot car state. This situation is mostly caused by the damage of input shaft or reverse clutch, or the damage of D/R brake. It may also be that the automatic gearbox is seriously leaking oil and is seriously short of oil. The connecting rod or cable between the shift lever and the rocker arm of the manual valve is loose, and the manual valve is kept in neutral or parking position.
Common fault 4: the oil inlet screen is blocked; The main oil circuit is seriously leaking; Oil pump damage
Fault analysis:The impact and impact of vehicle shifting during driving is also a common fault phenomenon of automatic gearbox, which may be caused by too dirty gearbox oil, resulting in stuck valve body.
Common fault 5: the gearbox slips and the acceleration is weak; Transmission water inlet
Fault analysis:When the car is running, there is the sound of engine idling during the acceleration of the gas valve, and the speed of the car does not increase, which makes the whole car feel weak. This phenomenon is mostly caused by the burning of the clutch plate. Water enters the gearbox due to external reasons, resulting in abnormal operation of the gearbox. This may be due to oil in the water tank or water entering from the gearbox vent cap.
Common fault six: abnormal sound
Fault analysis:Abnormal sound can be divided into many situations. (1) is the abnormal sound of the bearing. Generally, the abnormal sound of the bearing is closely related to the rotational speed. The higher the rotational speed, the more screams there are.
(2) is the differential or main transmission gear abnormal sound, this kind of abnormal sound generally appears in the speed of 50-70 km is more obvious, because the meshing surface of the gear is not
Similarly, when refueling, the noise is obvious, and the noise of releasing the throttle is obviously weakened.
(3) is the abnormal sound of hydraulic system such as oil pump, which is closely related to the speed, but has nothing to do with the speed. When the speed is high, the oil pump is blocked to suck oil, which leads to screaming. It should be noted that the gearbox system works together with the bow | engine, chassis and other parts, and many sounds are mixed together, so it is not easy to identify it.
Common Fault 7: Odor in the box
Fault analysis:The gearbox works by hydraulic oil. When the oil temperature is too high, it will produce some combustion, and these peculiar smells will come out, which shows that some executive parts in the gearbox are not working properly.
Common fault 8: Automatic shift time is too long or too short.
Fault analysis:Generally, automatic gearboxes have a specific shift speed and speed. If it is found that the shift time is suddenly too long or too short, it means that the transmission ratio of the gearbox is out of proportion, and at the same time, it will feel that the engine speed is too high. What’s more, the gearbox does not shift gears, which indicates that there is something wrong with the gearbox.
Common fault 9: high engine speed while driving
Fault analysis:This problem is divided into two situations: high speed during steady driving and high speed during speed increase.
The high rotating speed during the steady process is caused by the failure of the high gear of the gearbox or the failure of the internal locking clutch of the button changer, so the gearbox needs to be repaired immediately.
The excessive speed in the speed-up process is controlled by the fuzzy logic of the electronic control system of the gearbox, so this standard needs a certain professional level to be completed.
Common fault 10: Engine idling
Fault analysis:Engine idling generally occurs in two situations.
First, when the vehicle is in a steady state, the bow and engine suddenly idling, and then it returns to normal when the speed slows down.
This situation generally shows that the gearbox suddenly drops from high gear to low gear in a short time, and the problem may be in the control system or cooling system, but there is nothing wrong with the gearbox itself.
Second, there is a short-term slip and idling phenomenon during acceleration or gear shifting.
The intuitive feeling is that the second one is not as powerful as the first one. In fact, it is just the opposite. Most of the problems of the second one lie in the clutch and other related links in the gearbox. It takes a lot more time and cost to deal with the complete disintegration and overhaul of the gearbox.
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