The next one I do,(1 down 4 to go
), I'll remove the rad, with the fans still installed, on a COLD engine this time, take my time, plumb it in, in series. The reason I would plumb it in series is because it takes less time, that and I change trans fluids at LEAST twice a year. Plumbing them in paralell has the advantage if one, (the rad) clogs you still have flow.