Subaru Power Steering?

I recently did a power steering flush on my 2002 Subaru Outback 2.5L. Now that the fluid has been changed while static turning (turning while not moving) the pump is humming real loud and it is hard to steer. I did not let the pump run dry during the flush and I used Dextron III ATF like recommended in the repair manual and owner's manual. When I look in the resivor, it is very sudsy. I turned the wheel with cap off to get air out, why is it sudsy? Is there a brand of ATF I should use? Or do the pumps go out on this particular vehicle common and this is a coincidence? Thanks in advance!