Symptom: a Jetta car, after driving the 140,000 km suddenly generated transmission (manual five-speed transmission) no reverse (not on the reverse gear) failure (forward gear normal). The car was replaced a month ago by the speed of the odometer drive shaft (hereinafter referred to as the drive shaft), and thereafter there have been abnormal sound in the transmission.
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    Troubleshooting:
    The test shows that there is no reverse gear on the transmission, but the forward gear is normal.
    According to the preliminary results of the test, there is a foreign matter in the transmission, which makes the variable speed control mechanism stuck and can not be attached to the reverse gear; and the foreign matter is dropped from the installation slot, is used to absorb the transmission parts of the transmission parts of the magnet. Therefore, it is decided to disassemble the transmission.
    After removing the transmission from the car, it was found that the gearshift of the transmission was normal. After the analysis, it was thought that this could be the result of changing the position of the foreign matter in the forward and reverse rotation of the transmission shaft during the demolition process, proving that there was a foreign matter in the transmission. In the disintegration of the transmission after the discovery of foreign body is the drive shaft on the transmission gear. It can be sure that the foreign body is a month before the replacement of the drive shaft due to repair operations caused by illegal workers. In the disintegration of the transmission also found that in the transmission gear oil is very small, only half of the normal amount. After the removal of the foreign body, re-check and replace the transmission and replace the gear oil (plus enough), the transmission without reverse fault is excluded.
    Some of the car's transmission is still mechanical five-speed transmission. The speed gauges of these cars are mechanical (with rotating magnets), which are connected by the drive shaft through the transmission shaft and the second shaft of the transmission. In the replacement of these drive shaft should pay attention to the following points:
    A. Remove the drive shaft from the transmission must not be brutal operation. Care should be taken when pulling the drive gear from the transmission shaft out of the transmission, and it must first be aligned with the hole in the transmission housing and then gently try to pull it out. If the pull is pulled, the drive gear of the drive shaft will be scraped off the transmission, making the original fault more complicated or creating a new fault.
    B. When replacing the drive gear of the drive shaft and installing the drive shaft, install one of the snap springs in the drive shaft of the drive shaft into the slot. When the drive gear is in place, When the slot is clear "click" sound.
    C. Now that the drive shaft on the market is not equipped with a retainer, the car repairman must keep the retainer on the old drive shaft when replacing the drive shaft. The best way is to keep the old retainer from the old Drive the shaft on the drive shaft and attach it to the new drive shaft.
    D. After assembling, check whether the installation of the transmission gear is in place and the connection between the transmission gear and the drive shaft.
    Note: There is a transverse view hole on the transmission gear, through which the retainer can be observed. If the retainer is not visible, the assembly of the drive gear and drive shaft is incorrect and requires reassembly.
    It should be noted that: Jetta car transmission, the main reducer and differential are combined together, collectively referred to as variable speed drive axle. It is designed and easy to operate, therefore, under normal circumstances the transmission failure is very small, usually in the maintenance of the transmission as long as the inspection and lubrication of its variable speed control mechanism, check and if necessary, replace the transmission gear oil can be.