2015 coasting noise

[Bhuynh]

I am a new owner of a 2015 Explorer Limited. Maybe I am just being paranoid, but I recently noticed that when my Explorer drives beyond a speed of 50km I start to hear a revving sound from the rear of the SUV. At first I figured it was just the exhaust or acceleration. However, the revving sound continues when my foot is off the gas and am just coasting. The sound goes away when my speed drops below 40km. Is this normal? I never noticed it before, or maybe my radio was on too loud lol. Any information would be great!

 

[Bhuynh]

Update:

I took the Explorer to get diagnosed at Ford. Apparently the noise can either be road noise or a wheel bearing (passenger rear). I do not feel any vibrations when driving, and the Explorer drives very smooth(besides the noise). My Explorer has only 9867km on it and is still under warranty. Has anyone else had an issue with a wheel bearing going this prematurely?