Common problems and faults: unable to lock the manual wheel hub (unable to hang the four-wheel drive): damaged switch, worn internal fork or gear.
Due to common problems and failures, the wheel hub cannot be locked (can't be hung on the four-wheel drive): the most common reason is that the vacuum pipeline leaks or falls off.
Unable to separate (four-wheel drive cannot be removed) the manual wheel hub: the switch is stuck, and the internal mechanism is foreign or damaged.
Unable to separate (four-wheel drive can't be removed) automatic hub: Similarly, it is mostly a vacuum problem, or the internal clutch return spring fails, resulting in the clutch can't be disengaged.
sound: the gear or bearing inside the hub is worn and short of oil, which will produce a "click" sound or grinding sound when combining or driving.