There is could be 2 options about differential lock:
If you talking about main differential - yes, in AUTO torque distributed not equally to the axles, but in 4Hi it's equal to rear and front. We have another system, similar but not the same as TOD, Nissan's system more intelligent (IMHO) and torque could be applied in some cases when it 'probably' will be required, when you push accelerator, for example.
If you talking about differential lock in axle - it will 100% apply equal torque and will synchronously rotate both wheels. It's necessary when you going hard offroad or if you know that you need to pass some place where your tires possibly will loose contact with the surface.
Sorry, for offtopic, I promise - tomorrow I will post some Real snow pics, not that good as in Norway but a lot of snow and Pathfinder, of course
Max