Symptom: start the engine in the parking state, release the accelerator pedal (either in the D or manual mode), do not continue to step on the accelerator pedal to accelerate, keep idle, and the speed of 5km / h under the slow straight, can clearly hear the chassis issued Rhythm of the "slightly deng" sound, and accompanied by a sense of vibration. In the steering no abnormal sound, more than the above-mentioned speed when no sound. No fault code. Check all transmission parts, ball head, rubber pad, no problem. Replace the splitter, rear axle differential, splitter motor, the fault can not be ruled out. There is no sound or vibration when the lane mode is locked in LOW or differential lock. But unplug the splitter motor wire plug, the fault disappears.
    Failure reasons: before and after the tire pattern, different brands, front and rear wheel diameter different sizes. The front and rear axles of the four-wheel drive vehicle produce different wheel speeds due to the different outer diameters of the front and rear wheels. In the full-time four-wheel drive, the drive torque should be evenly distributed to the front and rear axles without slip between the axles. If the axle differential lock sensor of the splitter control unit detects the difference in rotational speed between the axle, the torque difference is calculated by the control unit and the required pressure is applied by the stepper motor to adjust the diaphragm clutch to ensure that the front axle axle is not slippery Poor generation. Due to the difference in the outer diameter of the front and rear tires, the front and rear axles always have a speed difference, which may cause the splitter stepper motor to be damaged due to the high working temperature.
    Solution: replace the same specifications, with the brand, with tread tires.