I have a 2011 Subaru Outback limited with CVT an just over 98,000 miles. At about 47 mph I am hearing a hum.

This would depend on where the hum is coming from and how loud it is. If the CVT is working OK then I would not worry but you should have the CVT fluid changed if you have not done so.

If you're lucky it's either scalloped tires that you should rotate and rebalance to arrest this process...or a wheel bearing (probably rear) is wearing out...which is common. The former will hit you for $80, the latter about $200. I don't know if SOA will "participate" in a goodwill CVT change, and whether being on one side of 100k is meaningful in their decision process; so it may make sense to get your Subie up in the air and cruising along as a wrench with good hearing listens at all four corners for a noisy bearing (phew!) AND at the tranny for an emergent inner CVT bearing ($2000 used, $7k new!). A friend who runs a busy indie Subie store in CT is getting pissed at how many 2010-2012 CVTs he's having to replace. Sigh.... Good luck, and let me know what you find.

Thanks for your response. I hope to get my Subie in tomorrow so that we can know what is going on. It had occurred to us that perhaps it is a wheel bearing. The tranny seems to be working as it should, but it is good to check out before things get worse.

Thanks for you answer - I hope to get it in and find out what is going on.