Sentra 2.0 Roaring noise from under front of car

[chipahoy]

I have a 2007 Nissan Sentra S, 2.0, CVT with 130,000k. Recently, I noticed a loud "roaring noise" from underneath the car, increasing with speed, starting about 35-40 mph until about 65-70 mph where it tapers off and you no longer hear it over 75 mph. It sounds like the majority of the noise is coming from the driver side, but its hard to say. I could swear it was a tire noise as it changes with road surface, but I have rotated the tires and the noise is still there. I also put the transmission in neutral while at speed to see if it was transmission related, but it's still there. it increases and decreases with speed. Any ideas as to what it could be?

[centralcoaster33]

Does the sound change during turning? Is it present in reverse or even coasting in reverse? transmission is on the passenger side I believe, with a shaft going through to CV joints and transaxle, so maybe bad joint, seal or bearing? While rotating tires, did you "feel" your wheel while rotating it for anything that seemed unusual?