Noise from driveline, help with identifying please

[Bordbender]

Hi
I am experiencing a weird humming type noise from under my 1996 sport,
We have changed the diffy fluids, apparently this was no help.

Can someone please help us to diagnose where the noise is coming from?
Since we live in an apartment, it is nearly impossible to do any work ouraselves, however jtsmith said we could bring it to his house to do whatever. It would be a 2 hour drive, I'd like to be sure the truck could even go that far
Any help on where to start is appresiated

 

[Diddy74]

Where exactly does the hum seem to emanate from? under the hood or under the truck? Under what conditions does it occur? Idle,drive,acceleration,while moving? I could be a number of things. I know my "hum" was related to a sticky EGR valve it usually happened when accelerating. It was really annoying and hard to pinpoint.

 

[Bordbender]

It is coming from under, when driving down the road, the faster it gets the faster and louder the hum gets, can't tell if it's up front or rearend. Maybe wheel bearings?

 

[Turdle]

Ine reason I had you get on here is because youe transfer case is different than mine.
Does the noise change when you shift into or out of 4WD?.

 

[Turdle]

Just a tatse of the info you can get here

http://www.explorerforum.com/forums/showthread.php?t=165429&highlight=front+hub+bearing

 

[Bordbender]

Haven't had to put it in 4 wheel drive for a while. Don't know.

 

[Turdle]

The reason I asked, if you switch to 4wd and the sound changes, that might help narrow down where it comes from.

Does anyone have any ideas?

 

[boominXplorer]

I would cheack front bearings for play. Jack the front tires off the ground and see if there is any play.

 

[Turdle]

Here is another with the same problem
Maybe someone between you all will get it

http://www.explorerforum.com/forums/showthread.php?p=1509496#post1509496

 

[rabbit]

Also check the condition of the tires. Any funny wear (heck even regular wear sometimes) or balancing problems will cause a highway hum. Aggressive treads make more noise. Try rotating your tires front to back and do a ball joint/tie rod inspection while you have the tires off.