Way back in the 70s and 80s some 4 wheel drive vehicles had front wheel hubs that could be locked and unlocked manually.

The knob was at the wheel.

Unlocking the hubs was recommended for summer use to reduce tire wear and improve gas mileage..maybe 1 or 2 mpg.

Pulling the front drive shaft has a similar effect since it elimantes the parasitic losses of the front differential...the rear is doing all the work.

The question is how will the computer react.