2004 Expedition 5.4L 4WD. It has 89K on it and now I continue to hear a howling noise like a tire noise first thought to be at the right rear. It has been getting worse. The tires are Goodyear Wranglers with only about 10,000 miles on them and look close to new. Never had a noise before. The sound is the same noise I used to hear in conventional rear ends that had axel bearings going out in them that I often fixed. But I don't know if this new type of independent suspension allows that?? The sound is always constant weather coasting or braking or acceleration. Never varied except with RPM as it was more noticeable after 35 MPH. However, what bothers me is that It didn't do it all the time and now does. At first, it softened when on the road longer. Now it is pretty constant.
So I bought the new axel grease to change it with friction modifier in it and thought I could try that after hearing all the complaints about noisy drive lines and lim. slip clutch plate noise from these threads. But that didn't help.
Then I read threads about this usually coming from the front axels. So now I notice that when I turn the noise gets louder as soon as I take off and turn to the right or the left. I am now thinking that one of the front right axels is bad. Each front axel has the sealed unit close to the hub and a cv joint with cover on the other end at the differential housing. The manuel shows this one can be lubed by taken off the rubber boot.
How can I be sure which one it is? right or left and if it is sealed bearing or lubricated cv? If I do it myself, that is one thing but I don't trust a mechanic to have to end up replacing all four wheels to get the right one that is bad.
I am thinking of raising both rear wheels on the jack w/stands and blocks and running it to see if I can pin point the noise if it is the rear. But it sounds now that it is in the front. I read that expedition commonly have drive line problems. Can anyone help me pin point this problem?
Cornell's emal

 

From your description it sounds like one of the wheel hubs needs to be replaced.

 

Thanks Alloro, Can I look up this on a thread or something w/pictures that you know of? I think the wheel hub is the Sealed bearing on the hub side of the axel but not the differential side of the axel which is able to be lubed? Am I correct?
I looked at a Chilton manual which wasn't satisfying but shows that I can remove axel by taking off wheel, remove drive axel hub nuts on the outside then drive axel flange bolts on the inside then removing hub assembly from steering knuckle bolts. And then tapping hub assembly from side to side to loosen from the knuckle. But I read somewhere else that you have to take out the springs to replace the axel to differential seal which is barely leaking. Is that necessary and how is that done?
Confused

 

Ok, I lifted up the rear of vehicle to detect if the axel noise is coming from the rear. I ran it to 70 mph and it sounded really quiet to me. I used a broom stick to my ear at appropriate places on the rear end as both rear wheels were spinning at various speeds. It sounded really quiet. Then with closer listening I detected a very subtle intermittent hum after spinning @ 70 mph. But I dismissed that sound as nothing. But up in the air, with no weight or drag on it I wonder if it will give off any noises??
But when I took the expedition on a small trip, I sat in the back seat and the noise sounded again like it was coming from the right rear. But on the return the front sounded noisier like the right front. I am really confused now. I know there are a lot of people out there that must have had this problem. I would love some more ideas. As I am getting ready to take it to the shop which causes me to admit to defeat.

 

See alloro's post below from a previous discussion. This should be helpful.

https://www.ford-trucks.com/forums/1...tion-time.html

 

Thanks r2millers for this direction to the posts. I printed them out. Is the '99 Expedition 4x4 front end the same as my '04 front end comparing axel repair? I know there is a differential clip difference but that shouldn't hinder mine.
Thanks to all.