I have a 2009 town and country with a 3.8 liter engine with 125,000 miles on it.
about 4 months ago it started making this humming noise from the rear end, that increases when the van speed does as it gets louder it seems to make a pulsating noise and humming sound.
I have checked the wheel bearings and they seem fine I also rotated my tires too, which are newer tires. the sound is driving us crazy, if anyone can help we would appreciate it very much

 

Did the noise move with the different tire position? if so then a bad tire(slipped belt).
If not, then bearing or brake pad hanging up on that corner.

 

Open your petrol flap and remove the cap and place ear to the filler hole. Is it more noticeable.