It's a very small inside diameter, so you won't move a lot of air. If you think air is getting through, that should be enough to vent.
Probably just a leaking seal then. We've ALL had one, or more. I've replaced three myself (one on my ride and two on TheCaptain's).
It's straightforward. If you haven't opened and inspected your hubs before, it's a good idea anyway. Always good to check your bearings and gears in there, then reseal the access ports and replace other seals as needed. Sort of like changing the plugs and air cleaner on a car you just bought used, they may be OK but only when YOU do it can you be certain of when it was last done (and done well). Good time to wire brush and repaint them too, if they haven't been done in a while. Kinda like owning a house, the repairs are never finished....
BDGR