2004 G 35 sedan, Im hearing a humming sound mostly between 35-40 mph coming from the back. I have new tires, differential oil is good.

Wheel bearing or differential bushing?

Thanks

I don't have an answer for you, but I have a friend who's 05 G sounds like a Cessna is following him down the road. He has never checked or changed his differential oil, so who knows... Please post up here if you figure it out.

I would say more than likely it is the wheel bearing. I have an 06 coupe and just replaced all four wheel bearings having 3 of them bad. Had a howling sound coming from rear and finally replaced it. Then I was able to actually hear that the front ones were bad as well. I think the differential bushing would be a little more noticeable than a humming sound. I am curious to know what you find/found out it was though.