Heavy truck 12 gearbox high-low changeover valve leaks.

When the temperature is low, the O-ring in the H valve is easy to deform, and the sealing performance decreases after deformation, which is easy to cause air leakage. Under normal circumstances, if the weather is cold, it is normal to change it several times. If there is still air leakage after several switches, only H valve can be replaced.

The fault of gearbox is mainly due to the dirty valve body, which will destroy the quality and friction characteristics of gearbox oil. Increase friction and wear, at the same time, sludge will also be produced in the gearbox, which will cause the valve body and pipeline to be blocked and the oil pressure cannot be adjusted in sequence, thus causing gearbox failure.

In this way, the solution can be found by searching for "no disassembly and no repair to solve the gearbox fault", without any damage to the car, and the oil change cycle of the gearbox can be extended by 3-5 times, effectively controlling the oil temperature of the gearbox.

Judgment and inspection principles of abnormal sound and shift failure of gearbox;

1, first simple, then complex, from the periphery to the inside.

First, first of all, from the simple cause of the failure.

B, in order to determine the complex fault.

C. find out the cause of the fault and the assembly of the gearbox.

D. finally decide whether to disassemble the gearbox.