Is it normal for a diverter valve to slowly drip from the inactive work ports or do I need to get a new one? It drips about one drop every three seconds.
I think you know the answer...no leaks are normal in hydraulics, but yet there always seems to be some minor seepage, at minimum. Active dripping like that indicates it needs to be tightened, re-sealed, or replaced.
Oh - hold on - I didn't read close enough. You mean that a little gets by the spool into the aux ports. I suspect that is very common. Plug the ports if for some reason you don't have capped lines attached to it.