Caution: To avoid damage to transmission components, partial loading is prohibited for 4WD models (by raising only one of the vehicle's axles).
4WD vehicles have permanent all-wheel drive, the so-called "Full time 4WD" (interaxle differential system). This allows for optimal distribution of torque between the wheels, but when slipping, a situation may arise where the torque is transmitted only to one wheel, which has the least grip on the road. To prevent this situation, the interaxle differential lock is designed.
Models with manual transmission are equipped with an automatic center differential lock system (viscous coupling). This system does not require driver intervention, but does not provide 100% locking and the clutch is activated with a slight time delay.
All-wheel drive diagram.
1 - interwheel differential,
2 - center differential,
3 - viscous coupling.
Models with automatic transmission are equipped with an automatic center differential lock system "C-DIFF AUTO". When you press the button "C-DIFF AUTO" the system automatically selects the differential lock coefficient depending on the wheel slip.
[See the source on the internet resource ToyotaMAN.ru]