OK. Thanks. Still I do not understand how this locker is activated, it obviously must be locked in one or another way because the behavior / difference regarding 2WD / 4WD is quite obvious. The jacking method could be used to test rotation direction on rear axles when it is placed in 2WD mode, but ...

Toyota Hilux, 2003 mod, 2,5 TD / D4D /SR5 / type KDN 170 / 2WD / 4WD / high / low, no installed switch for rear diff lock activation, no electric locker, no vacuum locker or any other patent is to be observed on the rear differential. When operated in the 2WD position it is almost like any other car ...