My method is simple:
Transfer case is usually in Auto, which is where I leave it.
I brake to a stop at the top of the steep slope.
I put the truck in neutral using the automatic gear shift knob on the dash.
I reduce brake pressure until the truck starts to roll (from gravity) and I keep the speed to barely moving.
The antilock brakes usually activate when a wheels skids.
If they don't, I reduce brake pressure until I can steer. Then I slowly reapply the brakes.
I don't try to stop the truck on the slope. I just try to keep the speed as low as possible without stopping.
The goal is to go down the center of the road, stay out of the ditch and off the cliff.