Discovery II(Edit)
Full-time all wheel drive. Four-wheel electronic traction control. Active cornering enhancement system. Hill Descent Control (HDC). Full-floating live axles front and rear. Unlike on the MB ML-class - it needs only 1/4 - 1/2 of wheelspin to detect the need of traction control activation.
The linkage between the Hi/Lo and diff lock engagement lever was removed on Discovery II, because the traction control system was supposed to perform the functions of locking differentials and Land Rover believed a real differential lock was not needed. However, eearly Discovery still have the transfer box internals. It is possible to order the linkage and connect the differential lock lever (http://www.discovery2.co.uk/diff_lock.html).
Then differential locking mechanism was removed from the transfer case, but introduced again by the end of Disco II life.

Discovery III(Edit)
Full-time all wheel system with lockable center and rear differentials. 50/50 torque split. On vehicles with air suspension - Terrain Response electronically-controlled full-time all wheel system.
To use it, a driver turns a small knob on the center console down between the seats to choose among five usage or surface settings: (1) general mode, for everyday driving, (2) grass/gravel/snow, (3) mud and ruts, (4) sand, (5) rock crawl. For each setting, Terrain Response adjusts the differentials locking ratio, traction control system, hill decent control system, anti-lock system, and suspension height to perform best for each driving condition.
Figure: Terrain Response mode selection knob (top), yellow HDC button, on the left - suspension height adjustment switch, and low gear switch on the right

Figure: Terrain Response status is displayed on the dashboard

Series I 1948-1954(Edit)
there was a 4wd system without center differential in the beginning, with freewheeling device up front for tire-scrub reduction. From 1950 - dogleg clutch is used to disengage the front axle.
Range Rover 2002-...(Edit)
?
Range Rover Evoque AWD 2011-...(Edit)
Haldex generation IV? proactive automatic all wheel drive. Normally a front wheel drive vehicle. Terrain Response system which adjusts engine torque, all wheel drive and traction control systems operation based on the program selected by driver.
Figure: Terrain Response system switch on Range Rover Evoque AWD

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