I have a 16 3.5L CC 4X4 XLT with 3.31. 59k miles. I have a 2" leveling kit in the front.

Over the last few months I have been noticing a front end hum that has been getting worse over time. The hum is most pronounced during acceleration, and whines down to a drone during deccel.

I assumed this was related to my tires wearing, and being on their last leg at 60k (265/55/r20 Hankook Dynapro A/T).
Thinking this was the issue, I had new tires installed today - 265/55/r20 Goodyear Duratrac.
The hum is still present. I don't believe this is related to the vac check valve as it does not go away when 4WD is engaged.
Most reviews I had read on the duractracs said they were pretty close to stock noise.

Here are a couple videos I took - one under light accel, and one accelerating slightly harder.




Any other ideas besides the check valve? I have not had a chance yet to get under the truck and look for other possible causes.
Thanks

 

I only saw one video, but my bet is wheel bearing. When you turn does the sound change?

 

No, I thought wheel bearing too but no change when turning left or right.