Syncro Diff lock test

The rear differential lock is controlled by a vacuum actuator. The actuator starts pulling on the locker fork immediately when you pull the knob. But it cannot engage until the axles rotate a little. It could take up to 1/6 of a turn of the wheel for the dogs to align, then it locks.
In this test I am driving in a circle on soft dirt, with the steering turned at full lock.
Before the differential locks, the wheel is simply rolling on the soft dirt because the differential allows the left and right wheel to 'adjust'.
When the differential locks, the wheels are now connected together with a solid axle, and to negotiate a turn, the wheels must slip on the dirt.
You can see the moment when the differential lock, the tire starts to scrub forward on the soft dirt because its being driven faster than its contact speed on the dirt. The other tire is being dragged on the dirt, it's turning slower than its contact speed.