Strange noise behind cab w/6.0

[sunnydude]

Had truck for 500 miles.  When idling you can hear a whirring noise coming from behind the cab.  Noise escalates as you increase speed, but goes away when you let off gas the sound disappears.  Is this a fuel pump noise?  Only complaint i have so far with the truck.

[CMNTMXR81]

The fuel pump is a constant buzzing no matter what you're doing.

 

Sounds like something in the drivetrain, particularly the rear end.  If it's hush, hush, almost nearly inaudible noise, that I would consider normal.

 

It escalates as you accelerate because you are on the front/drive side of both the ring and pinion gears.  It goes away when you let off because then you get on the backside of the ring and pinion's (or it could be vice/versa).

[sunnydude]

I wish it was hush hush, thats the problem.  You can definately hear the noise at highway speeds and it is anoying.

[Shaners]

This isn't the truck in your sig is it?  

 

What config is it? reg cab/excab/crewcab?  Shortbed or longbed?  4x4?

 

I wonder if it is a universal joint, or if it is a "longer" configuration like a crewcab or excab long bed then it could be the carrier bearing.

[knuts]

What about an exhaust leak and you hear it through the vents on the back of the cab??

[BDBWTE]

Got a tool box??? mine backs all kinds of sounds as you travel through the speeds...I like to think of them as adding character to the truck...

[sunnydude]

Thanks for the replies.  I forgot to change my profile to reflect the new truck.  Sound is there whenever you push on accelerator.  Let off and you can't hear it.  Dealership i bought from said to get 1000 miles on truck, if sound still there then bring it in.