you may wish to remove the reservoir and clean the internal mesh screen. before i do a fluid change/flush, i usually drain part of the reservoir, refill with seafoam, drive for a day oe two, and then completely flush it out with new fluid.
I am a fan of this, too. Thought I would have to rebuild a pump but this cleaned it up.
However, if you are not going to do a subsequent full flush (and it is NOT hard to do that), be very parsimonious witrh the amount of SeaFoam or B-12 as it really thins what is already a thin oil.