You can't expect anyone on your team to run a process the way you do if you haven't shown them how you do it!
Your basic mistake is optimizing for your current position instead of your next one, which is going to hurt you both in your current position and in seeking your next one. I think we sometimes have this thought process that, if things are currently going well for us, if we continue as we have been, things will continue to go well; there's more risk in changing, even if for the better, than to maintain an acceptable status quo. That's wrong.
It's certainly possible that, if you share your knowledge, one of your teammates will surpass you in skill and take over your position. But in order for your teammate to take over your position, the position must be available, so you may be promoted. Even in the doomsday scenario in which you're dismissed as redundant after you've shared your knowledge, you retain your leadership skills and successes to discuss in interviews for your next position. Regardless, you'll get a happier and more effective team (and likely better performance reviews), possibly a raise, and definitely more comfortable vacations.
It is also possible that, if you don't share your knowledge, your superiors will hear complaints from your team—keep in mind that, if you think your teammates are vying for your position, it's probably because they think they'd make a better leader (from what you've said, they're probably right); if you become a better leader first, they'll likely back down—realize that your team is turning out suboptimal work, and bring in someone who can and will share her knowledge to take over your position. In this case, it's not likely to be one of your teammates, as you hadn't trained them, but an outsider. And from where does the money come to pay for a more effective outsider? From your salary once you've been dismissed or demoted you for poor performance, which doesn't leave you with much good to discuss in future interviews.
The problem you're seeing is a symptom of a larger one, which is why none of us can offer quick-fix "just have them send a daily check-in email" advice here; you can't treat cancer with aspirin, after all. No matter what you do, you'll soon have plenty of "vacation" time, but if you choose to share your knowledge instead of greedily clawing your current position, you're more likely to also have the money to pay for it.