If you don't want to go all out with the flush DIY, try replacing part of the fluid by using the fluid pump you can get from part store and drain the reservoir. Fill it with new fluid and repeat it several times after driving around.
It's the lazy way of flushing, but, in my case, it actually helps smooth things around. It only takes 5 minutes per "flush." I just keep doing it everyday until I finished with the bottle.
BTW, I'm guessing this thread should not be in the detailing forum...