Ok my Durango suddenly started to make this wind noise or maybe even a hum when going speeds at or below 30. Checked all tire pressures, normal. Check to make sure there is fluid in both diffs(just did them before winter), normal. Checked all fluid levels, normal and good. Checked my u-joints and they were good too. Sounds like its coming from the rear of the truck, but noise does tend to travel at times. You would think as you go faster it gets louder but it actually goes away. Anything helpful would be great.

 

At the lower speeds, does it sound it under the driver's side?

 

Sounds like what mine sounded (except the noise going away at higher speeds) like when my rear Diff developed gear noise..

 

I'm not sure. I can actually here it more if the windows are up rather than down. What could it be under the driver side?

And old school the only reason I know its not making noise at higher speeds is cause I brought the truck up too 60-55 mph threw it in neutral and turned the truck off. Once I slowed down enough the noise is there.

 

There is a large bearing in the overdrive unit thats fails at times, Most people think its in the transfer case.

 

Would/could that bearing make that noise at low speeds?

 

I know you said you checked all fluids, but my power steering system makes the same noise, and it goes away once I get out of first gear. I had my lines replaced a few months ago due to excessive leaking, and the noise remained.