Thanks for previous help but I am still stumped as to why my E.Baur '04 Expd 4x4 w/5.4 eng. is still noisy. And I have been looking at threads for 6 months still trying to get a clue. Call me desperate.
Road/Gear Noise Started @ 89K miles and now have 100K. It was suggested that I change front wheel bearing hubs. So I had a shop in California that specializes in gears etc. change them both and while there he changed my right diff. housing bearing seal as it had a slight drip. It sounded like more work than I should attempt as a senior so I had someone else do it.
But the noise is still there. Starts around 35mph and increases in pitch the faster you go. The noise doesn't change with thrust or braking or changing gears or coasting in neutral. Noise is constant with the pitch frequency changing only with how fast the wheel rpm is. But once in a while if I go over dips in the road the noise makes a warble sound with change in pitch at the same speed. This seems important to me as the front wheels must flex on the springs and change the noise some how. But only when the smooth dip in the road is substantial.
The mechanic put car on jack stands and used stethascope to listen all turning points. There was some noise at the front differential towards right axel shaft bearing seal. And there was a noise at the rear differential where the drive shaft enters the diff. housing. The latter, the mechanic didn't think was an issue but wanted to pull out the front differential and repair that. Since that must be a big job I wanted to wait a while to be sure since I already spent $750 with no luck.
I had already replaced the rear gear grease with synthetic grease that had friction modifier in it. So after his test, I added an additional bottle of friction modifier which helped the noise I had turning during acceleration from a stop helping the clutches in Lim. slip.
So now I had to do something with front differential and I was frustrated so I added a little more grease in it and about 4-5 oz. of STP. It still was within the 1/2 inch below sight hole that is recommended. And it never had a history of going down below that. And this seemed to quiet it slightly so maybe we are on tract. Is this a common problem? Most of the miles are highway miles and I never abuse the car or hardly go off road even. And I bought it new. I don't know if I should let the mechanic pull that out to hopefully find the problem. Any help would be appreciated. see email below.
Cornell, thecruiseguy@comcast.net

 

Just curious, but what make/size/tread pattern tires are you running?

How many miles on the tires?

And how many miles on the tires since they were last rotated?

 

The tires are Goodyear Wranglers designed for SUV and original size. They have semi aggressive tread. They are supposed to get about 55,000 miles of life and have about half that now and still look good.
They are rotated often at about 5-8,000 miles.

 

The advice on wheel bearing noise was probably correct but unfortunately it is the back bearings that are going bad. If you can jack up the back and and put it in gear with some one listening to it spinning 40/50 mph it will be obvious if it is a bearing.

 

Thanks Twigs, but we checked all wheels with whole car up on stands and listening device. Back is quiet except yoke where drive shaft comes in and mechanic wasn't worried about that as if it was normal. And that is his expertise as his shop is called a name that has gears in it. Still stumped.

 

I'm not going to say the shop was wrong, but I've experienced the same symptoms you described and didn't have any detectable noise when turning the tires by hand or spining without the weight of the car on the wheels and it's always been a wheel bearing. Drive line noise is generally a high pitched howl that changes with the load, CV shafts a popping and shaking under load and sealed wheel bearings a low grawle starting at 35/40 mph going to an annoying hum you can feel at 65+ mph.
Just my experience and I hate the feeling of throwing money at it, hope you figure it out.

 

Cornell1 -
Did you ever find a solution/determine what caused the front end noise in your Expy? My 2005 4x4 Expy recently started making a front end noise. The noise, which seems to be coming from left front, is audible after the vehicle is drive from 5 to 10 minutes and sounds like a squeal or chirp. Dealer replaced the left front wheel assembly but the noise is still there.

 

Are the brakes old and worn down?
Have the CV joints been inspected?

 

I still have the noise. It sometimes isn't bad then it can be worse at other times. I am wondering if it is driveshaft cup bearings as there was a definate noise detected when putting hearing aid on the front of the rear differential. And the only time the noise varies is when I go over a "roller coaster" smooth road that allows the weight of the vehicle to vary. Like maybe the driveshaft is flexing due to spring movement. Maybe I should remove the rear drive shaft and place in Auto 4x4 or even lock it in to 4x4 high and drive it. They say it is really hard to remove the front drive shaft.
Has anyone done this maneuver before. I don't think it would hurt anything. Or does anyone know if '04 Expeditions have had a history of bad drive shaft bearings starting @ 85K and now at 100K?
On yours, If you had a new front hub put in on left side they should have looked at the brakes. If not she should inspect them for you since you still have the noise.
Cornell