Siren like noise between 25-35mph

2002 double cab 3.4 auto, I'm having a hard time trying to find the cause of a siren like noise between 25- 35 mph. It does it coasting or accelerating. In neutral or in drive. Throttle in neutral has no effect on the sound. Noise sounds like it coming from the front through the dash and floorboard. Any help.would be appreciated. Thanks.

 

I know that when I had bad wheel bearings on my jeep, it made an awful loud sound. I don't really remember what it sounded like, but it was super loud and gave me a headache. Since you say it does it while coasting in neutral and also accelerating, I would check the wheel bearings first.

 

you could eliminate everything on the front of the motor by removing the belt and running the engine for a short period of time .
Diagnosing sounds are difficult over a keyboard because everyones defenition of sounds are always different . Sometimes a video helps but best bet is removing the belt becuase when the belt is removed it elimintaes soooo many possibilities

 

Tried everything you guys suggested, no change. I even changed center support bearing, no change. Wheel bearings check out fine. This has got me puzzled.

 

Is it speed related...et.al., does the noise get louder or different pitched with variations in speed..?

 

Gets louder till 40mph then gone.

 

Or it gets so high pitched it becomes inaudible to the ear...you sure its not wind related..something whistleing thru the frame/under carriage...?

 

Kinda what I was thinking but its the same speed every time.