An annual output of Honda Accord 3.0 sedan (CM6), equipped with BAYA 5-speed automatic transmission. According to the owner to reflect the car in the process of running there have been the phenomenon of transmission slip, but the failure time is uncertain, so there has been no thorough inspection. During the last high-speed running, a large number of transmission oil was ejected from the upper vent of the transmission case, causing the vehicle to continue to travel and being towed into the repair shop.
    According to years of experience in the maintenance of automatic transmission, because the lack of transmission oil caused by the fault is relatively easy to repair, generally only need to check out the cause of the transmission oil temperature is too high and replace the ablation of friction parts and other components, and then the transmission internal cleaning You can solve the problem. First check the transmission oil, from the transmission oil contained in the impurities can be seen inside the transmission has been severely ablated, so decided to disassemble the transmission. After disassembling the transmission, check the status of the components and find that the drive gears and driven gears of the transmission pumps are severely burned and that there are multiple degrees of ablation of the clutch friction plates. Replace the transmission oil pump, the main valve body and burn the friction plate, and clean the transmission inside.
    In this need to remind the maintenance staff to note that the transmission oil from the main valve body, through the transmission housing on the oil path to reach the clutch, the middle of the oil on the road there are many seals, these seals are allowed to have a slight leak, But can not exceed the limit. Many maintenance personnel in the inspection of the clutch is generally only the use of compressed air on the clutch piston for a simple compression test, by observing the clutch piston action to determine the clutch is good or bad, in fact, this is not appropriate, due to excessive oil pressure caused by clutch filling Oil time is too long, can cause the transmission shift process slightly slippery or running in a serious slip and other failures. 800 kPa of compressed air is applied to a single transmission oil storage tank, the transmission oil from the tank can be adjusted to 600kPa pressure, the use of this pressure to drive the clutch, and then use the dial gauge to measure the clutch piston stroke The In accordance with the above method, the use of the United States Senaikesi transmission oil flow meter to test the amount of leakage of the clutch and the use of thousands of points to measure the clutch piston stroke, the data are in line with the requirements.
    Although many models of the transmission valve body problems are higher probability, but the Honda cars in the BAYA type transmission solenoid valve a lot of mechanical slide valve is very small, and has been carefully checked and replaced the main valve body, so There should be no problem with the gearbox. Assembling the transmission after loading, filling the right amount of transmission oil after the road test, but soon there is a problem, although there is no obvious sense of slippery transmission, but the block shift process is not soft, and still some poor acceleration. Engine speed at 2000r / min, 5 block speed is 100km / h, and the normal speed difference of about 20km / h, what is the reason? Is the torque converter lock problem? By observing the data flow can determine the torque converter There is no problem with the lock, and the system is stored without trouble code. It will not be a problem with the assembly, because the BAYA transmission is very familiar with the operation process is carried out in accordance with the maintenance manual. According to the transmission gear range can be judged, the transmission system is no problem, but the transmission ratio is not right. With the doubt, reviewed the characteristics of this transmission. BAYA transmission in the transmission using a parallel axis, the transmission includes six forward clutch, a one-way clutch, three shift solenoid valve (A, B, C), three clutch pressure control solenoid valve (A, B , C) and 3 and 4 block pressure switch 1 each. Because of the internal assembly of the transmission more confident, so the focus will be on the shift solenoid valve and clutch pressure control solenoid valve, because they directly determine the transmission gear and gear shift process. When checking the clutch pressure control solenoid valve A, it is found that the slide valve is stuck in the partially open position and can not return to the fully closed position, and the solenoid valve must be disassembled. The spool is mounted in the direction of the solenoid valve. After removing the solenoid valve, the spool valve is removed and it is found that there is a lot of corrosion at the top of the solenoid valve at the top of the spool, and the impurity is caught at the top of the spool so that it can not be returned The After cleaning the valve, the test drive troubleshooting, the vehicle acceleration is strong, the engine speed at 2000r / min 5 block speed can reach 120km / h.
 Why is the clutch pressure control solenoid valve A card lag will appear shift shock and acceleration failure? Clutch pressure control solenoid valve A the correct position, where the slide valve is in the closed position. The position of the solenoid valve A, where the slide valve has a certain degree of opening. Electromagnetic coil control the movement of the core, in order to promote the slide valve to move, so as to achieve the purpose of controlling the amount of oil.
   (1) When the transmission is in the 5 gear, due to the slide valve has a certain degree of opening, which led to a part of the CPCA (clutch pressure control valve) the role of the pressure on the clutch in the 4, resulting in the engine power in the 4 block on a certain Loss.
    (2) When the transmission is in the 4 gear, the clutch pressure control solenoid valve A is normally open, there is no problem of poor return, so the basic impact on the vehicle.
   (3) When the transmission is in the third gear, because the slide valve has a certain degree of opening, which led to a part of the CPCA pressure on the clutch in the 2, resulting in the engine power in the 2 block on a certain loss. For these reasons, it will lead to engine power shortage and speed ratio is not normal situation. After the car is removed, the owner drove the factory. But after a week or so, the transmission has appeared in the previous fault, and the fault is more serious. Call the fault code, the fault code "clutch pressure control solenoid valve A fault" to check the clutch pressure control solenoid valve A, found that the internal slide valve and stuck, but clean the valve after the failure did not disappear. Because the transmission oil in the metal powder, so once again disintegrated transmission, disassembled and found the transmission pump has a slight wear and tear, the main valve body on the majority of the slide valve has been stuck, 5 block clutch plate ablation, 4 block clutch plate has a slight overheating , Which also proved the last maintenance of the principle of the correct analysis, that is, when the transmission in the 5 block, the engine power in the 4 block will be a certain loss. Check the differential, found that the planetary gear shaft serious wear and tear, which should be caused by poor lubrication. Check the oil hole normal, along the oil circuit to check the transmission radiator and found a lot of impurities inside the radiator, indicating that the last maintenance is not complete cleaning. There are impurities in the radiator of the transmission, and the oil pump is worn, indicating that the impurities come from the torque converter. Because the torque converter can not be thoroughly cleaned in addition to refurbishment, replace the torque converter and differential, and grind the slide valve in the main valve body. After the completion of maintenance road test, transmission failure completely ruled out.
   For independently mounted transmission heat sinks, the flow rate can be measured using a transmission oil flowmeter, but the BAYA transmission radiator is mounted directly on the housing of the transmission, which brings a lot of inconvenience to the maintenance. Transmission heat dissipation system can not simply use the compressed air blowing on the line, must be thoroughly cleaned, if necessary, should be refurbished or replace the torque converter, independent installation of the radiator radiator must use the radiator flow meter to accurately measure the flow.