Behaviour of non-full-time FWD-based AWD systems. When does the AWD kick in?

[Eug]

Toyota's use of rear torque in their "AWD" hybrids from a stop has nothing to do with traction and is purely a function of maximizing the electric power to the wheels while the sleeping engine wakes up. On a hybrid with "AWD," there's going to be all kinds of weird behavior on the electric-only axle that has nothing to do with traction and is just about energy management.

Other people have already stated that some gas-only AWD vehicles behave the same way.

I even posted a link for a Chevy gas model that does this:

http://www.wheels.ca/car-reviews/2013-chevrolet-trax-a-compact-power-pack/

The article specifically states it was engineered this way to provide traction to prevent front wheel slippage before it happens.

Thus it would make sense that for the hybrid AWD system, that also is one of the reasons, but there is also the added potential benefit of increased fuel economy.