Q: cycling humming/buzing noise on highways 65-80 mph

cycling humming/buzing noise on highways 65-80 mph, the on/off cycling goes faster as fast as the car goes, from front driver side, I replaced the wheel bearing, it didn't help, I thought my next step to replace the cv axel, I noted a metal deposit on the cv axle end joint spline! it protrude on the smooth side of the spline, right after the grooves, its a silvery to dull gray metal, i think its Aluminum, I drained the cvt oil and it was clean, replacing the cv axle with clean one, it did a little deference regarding the buzzing/vibration noise, one more thing to add that i didn't see a bearing where the spline goes in, it was a bush! with a spiral carve (i guess for oil lubrication). can you tell what's the problem ? is there a problem with the differential ? how to fix that ? should i replace the whole transmission ? or wait till it fall apart before replacing it ? because so far other than the bumming/buzzing on high-speed the car is performance, how can you help ?

My car has 8000 miles.
My car has an automatic transmission.