That really only applies to old cars with old fashion fluids from the 60s. It doesnt apply anymore. And you cant completely flush the fluid unless you hook it up to one of the machines at some shops. When you pull the drain plug only about 4 qts comes out I think on those trannys, theres still another 8-10 sitting on the converter. And make sure you goto Nissan and get their fluid, you cant use regular Dexron/Mercon with the those Nissans like the old ones.