Trouble diagnosing noise in SUV

I have taken my 2002 Ford Explorer XLT automatic 4 wheel drive to 3 different mechanic shops - no one can determine what is making the noise my SUV is making. Being I’m not a mechanic, I need someone to figure it out so it can be fixed. 8 weeks and counting trying to get this thing fixed so I can feel safe about driving again.

The noise: a hard rubbing type noise with a circular/undulating type vibration or sound to it. Almost like a tire rubbing up against a curb with something out of balance. When it began 8 weeks ago, it only made the noise while driving at slow speeds making turns to the LEFT (such as town driving, stop-go-turn type stuff). It now will make the noise going straight when starting to accelerate from a stop and occasionally when making a turn to the right or backing out of the garage. It gets louder at times, used to be intermitent, but is now constant at slow speeds when making left turns and most take offs. Wheels have been looked at, jiggled, up on a hoist, brakes looked on the right side front & rear, told it doesn’t appear to be wheel bearings (all have been replaced at some point, even the rear differential bearings but that makes me a little nervous as this noise started after the differential was last worked on). Noise stops when pressing on brakes even when car is still moving. Noise remains if going slow down a hill and shift into neutral without braking. Noise seems to diminish right after SUV has been up on hoist or weight has been off the vehile but returns after driving a few miles that day. One time, had to brake suddenly and make a hard left turn, wow, it didn’t like that, it made the noise very loud for the remainder of the 60 mile drive - sounded like it was going to break something. Then, after car was jacked up to look at tires, then drove after that, noise was not as loud again. Some vibration in the wheel and from the floor at times. Mechanics cannot decide where the noise is coming from - front, back, they say it it hard to tell in this type of vehicle. I’m frustrated beyond belief and have spent so many hours trying to get this fixed before something major happens to it (no doubt while in heavy traffic). Any suggestions for the next mechanic shop I find?

chassis ear.

How many miles on it? Do you off-road with it?

The vehicle being a 4x4, I have to ask: Have you ever driven this vehicle on dry pavement with the 4wd engaged and turning during the process?

You said the noise started AFTER the rear diff was worked on. Perhaps it may be an idea to return there and have an inspection done. Pull the inspection cover off.

Seems no one around here has a chassis ear (if that is the expensive tool used to help locate origin of noises).

111,000 miles, have off roaded with it but not very much, mostly in snow. I’m told it’s all wheel drive with 4 wheel drive? It will auto lock if it senses it needs it during adverse conditions. They did try driving it with 4X4 engaged on dry pavement and did turns with it to see what is was doing (I don’t know why they did it or why you suggest this). No results I guess. I read something on the web indicating possible ‘spider gears’ but the shop isn’t thinking that’s the case. I suggested to the shop that worked on the rear differential that they look back into it, they are not wanting to unless there is proof that is the problem. The same place has worked on that differential 2 times. About 30,000 miles ago they replaced all the bearings inside it. Then this spring one of the bearings went again, which is what they did to it this last time (replaced one bearing). I’m tired of paying for all these bearings; can’t help but wonder if the mechanic didn’t get something right when it was worked on this last time but I can’t prove it and that may not be the case. I’m not eager to dish out another $600-$800 in labor alone to have it torn into again (already been there 2 times) plus if that’s not the problem… I’m fed up, frustrated, and my budget is tired of paying for it.

Thanks for your suggestions.

The wheel nuts need to be tightened to 245 ft-lb. I did one and didn’t have a suitable wrench. That bearing only lasted about a year and was an expensive lesson.

" The wheel nuts need to be tightened to 245 ft-lbs"???

Unless this is something new, I’ve never heard of a vehicle with all wheel drive AND a 4wd system too.

All wheel drive is a full time system and 4WD is a part time system.

If this IS in fact a 4WD system and it was engaged and used on dry pavement (as in turning) then damaged could have occurred in the transfer case.

Spider gears are in the differential like the one that shop worked on. I reckon that by now you already know this.

Don’t these bearings you mention have a warranty?

Perhaps you should find different shop for another opinion. (Independent drive-line shop)