Yutong Heavy Industry GJT112 bulldozer is a high-speed military bulldozer. It is known for its lightness and simplicity of operation and high work efficiency. This machine can quickly and efficiently complete tasks such as excavation, leveling and transportation. It is widely used in national defense projects, roads and airports. Under construction, etc. This article summarizes the common failure causes and treatment methods reported by most users and shares with you!

1: Phenomenon of too low gear shifting pressure and treatment method. Trouble phenomenon. When the engine of this machine is working normally, the machine feels that the power is insufficient during driving or operation, and it is unable to walk or walk slowly, and the operation is weak. Sometimes it is accompanied by the phenomenon of torque conversion and high transmission oil temperature.

cause of issue 

①If the transmission pressure of each gear is lower than 1.2MPa, the main pressure valve on the triple valve is improperly adjusted or damaged; or the oil pump seals or friction surfaces are seriously worn, resulting in leakage;

②If the gear shifting pressure is low, the main reason is that the gear pipe is not tightly sealed, the oil circuit sealing ring is damaged, and the piston sealing ring is seriously worn or damaged.

Troubleshooting method

① Check the quantity and quality of working oil, and adjust the main pressure valve to make the variable speed pressure reach 1.2MPa~1.6MPa;

②Check whether there is air leakage or blockage in the low pressure oil circuit, repair the oil pump, replace the seals and damaged parts;

③Check the oil leakage of the pipeline, and replace the damaged sealing ring or piston sealing ring in the oil circuit.

2: Torque converter oil temperature is too high. When the bulldozer is driving or operating, the normal working oil temperature of the torque converter is generally below 100℃. When the oil temperature at the outlet of the torque converter rises to 120°C, the oil temperature is too high.

cause of issue

① The amount of oil in the transmission oil pan is insufficient or the oil has deteriorated

②The transmission pressure is low and the shift clutch is slipping;

③The piston of the shift clutch cannot be returned;

④The oil return pressure of the torque converter is too low (＜0.15MPa);

⑤ The oil radiator is blocked; ⑥ The continuous high-load working time is too long.

Troubleshooting method

① Replenish the oil or replace the oil according to the specified amount;

② Adjust the main pressure valve to make the variable speed pressure reach 1.2MPa~1.6MPa;

③ Adjust the piston clearance of the shift clutch and replace the disc spring;

④ Repair the triple valve and adjust the outlet pressure valve so that the outlet pressure reaches 0.15 MPa~0.25MPa;

⑤Clean or replace the radiator;

⑥ Run at idle speed for half an hour or stop for cooling.

3: Failure phenomenon of mechanical walking weakness or failure. Mechanical walking weakness or failure is mainly manifested in slow movement and significantly reduced speed during driving, especially during work.

cause of issue

① When the fault occurs in all gears, the reasons are: (1) The transmission pressure is too low or the outlet pressure of the torque converter is too low; (2) The torque converter oil temperature is too high; (3) The shift lever fails; (4) ) The main oil passage of the control valve is blocked.

② When the fault occurs in a certain gear, the reasons are: (1) The block oil passage is blocked; (2) The friction plate in the clutch of this gear is slipping. 3) The fault occurred after the brake, and the reasons: (1) The brake linkage valve stem does not return; (2) The position of the air brake master valve push rod is incorrect; the return spring of the air brake master valve is invalid; The valve piston rod is stuck.

Troubleshooting method

① When the fault occurs in all gears, first check whether the transmission pressure, torque converter outlet pressure, and torque converter oil temperature are normal. If the pressure is too low or the oil temperature is too high, the triple valve should be adjusted or the variable speed oil pump should be overhauled. If the shift lever fails, the lever system should be adjusted or repaired. If the main oil passage of the control valve is blocked, it should be cleaned and dredged.

② When the fault occurs in a certain gear, first check the oil retaining passage. If there is a blockage, it should be cleaned and unblocked. If the fault is on the shift clutch, check the wear of the sealing ring, piston ring and friction plate, and replace it if necessary.

③The fault occurs after the brakes, usually caused by the brake linkage valve stem not returning. The speed control valve should be repaired. If the variable speed control valve is normal, the air brake master valve should be overhauled.