I noticed the noise comes and goes. Does it only hum when accelerating or coasting?
Sounds like the noise is only produced when something is under load. Could it be the pinion bearing in the rear end or even the rear universal joint? Just throwing something different out there for comments. It does sound like a bad wheel bearing, but the fact that the sound appears when accelerating back up to 45 makes me pause.Thanks for all of the comments/suggestions… noise is reproducible when the car is at running temp then decelerating then accelerating. Example 45mph down to 40 mph, during the re-acceleration from 40 to 45 is when the humming noise can be heard. Directionally the hum sound like its under the driver seat or toward the back I cannot hear the hum when parked and the hood up and revving the engine at low RPM. With the hood up I don’t here irregular sound from serpentine belt accessories. The car has to be moving to reproduce the hum. Driving with AC and radio off the hum can still be heard. There is no change in the hum when steering hard to the left / right. The hum has been heard for the last several months but now it is more reproducible (getting worse). The car is not a daily driver I just drive it once or twice a month because of front end work was needed.
Front end work completed: replaced tie rods, upper control arm, front brake rotors, wheel hub, on both sides of the car, Transmission fluid filter change and brake fluid. The local mechanic who performed the front-end work can hear the hum but not able to locate it. He spoke about using microphones. The local machinic will replace rear diff fluid on next visit soon
I think i am looking for a possible bad bearing ... just not sure were it is just yet