1. The compressed air of 0.7-0.8Mpa from the air storage tank of the whole vehicle is divided into two paths, and one path enters the air filter regulator of the transmission to provide working air pressure for the transmission to realize the high and low gear conversion of the auxiliary box synchronizer; the other path enters the air filter regulator. Power solenoid valve air inlet;

2. If the solenoid valve of the power take-off is not opened, the entire power take-off gas circuit system is airless and does not work. When the solenoid valve switch of the power take-off is turned on, the compressed air of 0.7-0.8Mpa enters the working cylinder of the power take-off and the neutral position cylinder of the auxiliary box respectively;

3. The air pressure entering the working cylinder of the power take-off pushes the piston of the power take-off cylinder to work, and the power take-off enters the working state;

4. The air pressure of the cylinder entering the neutral position of the auxiliary box will push the piston of the shifting cylinder of the auxiliary box to be in the middle position, so that the synchronizer of the auxiliary box is in the neutral position. The car does not move, and the power is taken from the stop.