2005 EB, 4wd, 4.6, 66K miles. I have read all of the other posts about the famous rear end whine but mine is different. It doesn't let up when coasting. Also changes to a higher pitch around 40mph. Just started recently. Had a 2002 with the famous whine but this is different. Any ideas?

 

Could be pinion or carrier bearings or possibly a wheel bearing. Got to get it up in the air with someone in the driver's seat going 40-50mph. Then get under it and listen for the source. Make sure you put it in 4wd high and disable advancetrac first.

 

same symptoms as i had in my 04, it was the carrier bearings pitted and making noise

 

IMO, If you jack it up and put it in gear and get it up to the speed you hear the noise. If you don't hear the noise, chances are its a wheel bearing.. I know someone said carrier bearing, Do they even have one?? Didn't think they where long enough to have one of those.. Check to see if the wheels feels loose when you jack it up because of the bearing having play in it also..