Another possible leak spot is the fitting going into the back of the passenger side head. It has a rubber ferrule compression fitting there that's a bugger to get at.
But if your drain tube is wet, that's likely the spot. As Oneof6 suggested, a drain valve rebuild or replacement will fix it up.
But if your drain tube is wet, that's likely the spot. As Oneof6 suggested, a drain valve rebuild or replacement will fix it up.