Whining sound during acceleration

[olbaldi]

My 2004 Expedition 5.4L2 has had a whining sound that rises with acceleration and stops when I take my foot off the pedal. When I start accelerating again, it starts again. This is my second Expedition and I noticed a similar sound with a 2000 model. It's not the tires, as replacing them hasn't caused any change. It seems a bit louder on the driver side. It's not a high pitched squeal, more like a consistent higher pitched moan. It is very consistent, not up and down (unless I take my foot of the accelerator. Any ideas?

 

[toms89]

Bearings??

Change with vehicle or engine speed??

 

[jjbusa]

You a I get the same noise from 42 to 65 MPH weird

 

[mindgame]

Rear differential?
http://www.justanswer.com/uploads/bkitchener/2009-08-12_162454_axle_noise.pdf

 

[rvm1]

I have the same model and problem. Fortunately, it happened when the Expy was 2 years and Ford replaced the rear differential under warranty

Sent from my HTC using Tapatalk 2

 

[FordandPolaris]

My gma's exploder had that signature Ford hum in the rear diff from the day she bought it. Never heard it in my expy though. Granted my exhaust would probably mask it anyways...

 

[mindgame]

Get one of these.. It works great, since I'm always under my Expy..
97202 - Steelman Tools

 

[01yellerCobra]

Sounds like gears to me. The pinion depth may not be correct. I've heard of the same issue when coasting.

 

[sgtowing]

Supercharger I know, I'm just being a smart ass.

 

[joezek]

Mine makes a loud whining noise under hard acceleration from under the hood. Sounds exactly like a supercharger, but quieter. It's not always there, only makes the noise when it's cold. I'm thinking possibly the power steering pump.