2006 Subaru Outback with Whirring and Recent Tire Thunking Noises

Hi Car Talk Community! I’m looking for some suggestions regarding my 2006 Subaru Outback. It has around 121000. I bought it at 113,000 last October since my previous 1998 Subaru made it to 240,000. So far I’ve taken it in for all new wiring and a tune up. And I was assured by the car salesman that the timing belt had been changed prior to my purchase. Anyway, since August I’ve had a rattly/whirring sound that I am experiencing over 15 mph. It seems to be coming from the back of my vehicle. It sounded like I had a hole in the muffler because it was reminiscent of when I lost my muffler on the highway with my 1998 subaru a few years ago, but this sound is definitely not as loud. The sound does increase in volume at high speeds on the highway but has so far not been as loud as my previous experience. (and the muffler is still there when i look under the car) When I took my car in to get the oil changed a couple months ago, I asked the mechanic to check and see if he saw anything while under there. They told me it was my heat shield. I’ve had that problem before as well which wasn’t really an issue but it definitely sounded more like a rattle than the whirring I seem to be having with my current car. Recently the noise started being a little bit louder on the highway so I thought maybe it was my tires since they were very due to be replaced. I bought new tires within the last few weeks and there has been no change with the whirring sound on the highway. Yesterday, I noticed a light thunking sound that started happening between the speeds 10-40mph. It seems to be in the front of my car and occuring with the rotation of my wheels. There are no sounds when Idle. Is this something pertaining to the new tires? Are these two sounds I’m experiencing related?

And thanks for your help/suggestions in advance!

The clunking is probably a bad CV joint and the whirring is more than likely a bad wheel bearing. Both will need checking out for safety.

Thanks for the input. I’ll take it in tomorrow. Is that generally an expensive fix?