How to change the transmission oil of a motor grader

How to change the transmission oil of a motor grader

The XCMG series of motor graders produced by our company have been continuously improved in recent years. With their strong cost-performance advantage, they have occupied a large share of the domestic market and entered the international market, covering more than twenty countries and regions, becoming one of the main exporters of domestic motor graders. Due to its stable overall performance, it has gained the trust of both domestic and foreign users. However, due to some users' lack of correct knowledge about usage and maintenance and improper operation, abnormalities occurred in the hydraulic transmission system, which once became the main problem of early fault feedback. The manifestations were that after the transmission oil was changed, there were phenomena such as weak system operation and excessively high system oil temperature. To enable users to master the correct usage and maintenance knowledge, and to enhance the service life and reliability of the motor grader, the requirements for oil in the system are analyzed now, and the following suggestions are made for handling:

I. General Requirements for Transmission Oil (Hydraulic Transmission Oil)

1) Appropriate viscosity;

2) Excellent defoaming property;

3) Good antioxidant stability;

4) Good viscosity-temperature properties.

For this reason, our company selects the hydraulic transmission oil as API CH-4 SAE 15W / 40 grade diesel engine oil.

Ii. Analysis of the Causes of System Failure

1) The original transmission oil was not completely and thoroughly replaced.

2) Failure to change the oil in accordance with the requirements and regulations stipulated in the product user manual of our company;

3) The specifications and grades of the oil used for replacement are not uniform, resulting in the mixed use of oils of different specifications and grades.

4) The hydraulic transmission manufacturers of our company are Liuzhou ZF Company and Hangzhou Qianjin Gearbox Factory.

The specified oil for the hydraulic transmission of Liuzhou ZF Company is API CH-4 SAE 15W / 40 diesel engine oil. The specified oil for the hydraulic transmission of Hangzhou Qianjin Gearbox Factory is 46 # Hydraulic transmission oil (formerly 8 # Hydraulic transmission oil), and 15W / 40 diesel engine oil can also be selected. Because 8 # hydraulic transmission oil produced by different manufacturers of the same brand should not be mixed and used, while multi-grade diesel engine oil produced by different manufacturers of the same grade can be mixed and used. Therefore, based on the performance requirements that multi-grade diesel engine oil has both internal combustion engine lubrication and hydraulic transmission oil, in order to simplify the oil grades, after June 2004, the oil for diesel engine lubrication and hydraulic transmission system of XCMG brand motor graders was uniformly changed to API CH-4 SAE 15W / 40 multi-grade diesel engine oil.

Iii. Correct Maintenance and Oil Change Methods:

1. Before changing the oil, drive the motor grader for about 10 kilometers to ensure that the entire hydraulic transmission system is fully circulated and the oil temperature of the transmission reaches around 40℃ (so that the oil can be drained thoroughly). Stop the motor grader on a flat surface.

2 Place the gear selector in neutral and pull the handbrake tightly. If conditions permit, wedges can be used to fix the tires of the motor grader to prevent accidents.

3 Loosen the oil filler hose (also known as the oil drain pipe) at the bottom of the transmission and drain the transmission oil from the bottom. At the same time, ensure the cleanliness of the rubber hoses and joints at the bottom of the transmission, and prevent rainwater from seeping in during rainy days to avoid emulsification of the oil.

4 At the same time, open the rear grille of the engine hood and loosen the return oil pipe connecting the radiator and the transmission (that is, on the side of the radiator return oil port, from the back to the front on the left side of the radiator).

5 The height of the opening of the connecting rubber hose is increased to facilitate the maximum drainage of the old oil. The drainage time for both oil drainage positions is 1 hour.

6 After draining the old oil, install the rubber hose and add about 38 liters of filtered API CH-4 SAE 15W / 40 multi-grade diesel engine oil from the fuel cup to the transmission oil bottom. The quantity may differ from the actual situation. It should be added in time to ensure that the specified quantity is reached.

7 Start the motor grader. At idle speed, let the hydraulic transmission system circulate and discharge the original system oil from the return oil port of the radiator until new oil appears at the return oil port of the radiator.

8 Reconnect and tighten the return oil pipe connecting the radiator return oil port and the transmission. According to the requirements of the user manual, check the oil dipstick and replenish the usage amount of API CH-4 SAE 15W / 40 grade diesel engine oil.

9 After replacing the transmission filter element and ensuring that all components of the system are properly connected, close the rear grille of the engine hood and put it into use.

Note that all the oil drained from the transmission, radiator and the return oil pipe connected to the transmission must not be refilled into the transmission.

In addition, the same grade of multi-grade diesel engine oil API CH-4 SAE 15W / 40 produced by different manufacturers using different crude oils and different processes can be mixed but not stored together. It is strictly prohibited to mix diesel engine oil of different grades with other engine oils.

Through the above steps of replacement, the used diesel engine oil can be replaced in a timely and thorough manner. This not only enables scientific maintenance of the equipment, significantly extending its service life, but also reduces the frequency of equipment failures. It can largely ensure the smooth completion of the production period and create greater economic benefits for users.