IMHO never do a flush. Sediment settles to the bottom, pulling it back up thru the system is almost the single worst thing you can do.

Transmission - drop the pan and filter run fresh fluid thru top to pan. Replace filter and pan.

Power steering - drain and replace

Cooling system - drain and flush DO NOT suck fluid back thru the system. Modern engines are sand casted and you'll pull silicates back into the engine.