so I dont know if I am posting in the right spot. But I have a noise that I thnk is the same as yours. Mine is the worst at about 120 km/h. Its a loud droning noise. It rattles your brain and makes your head hurt. 10 minutes of highway driving with that noise and I am so irritated that I want to kill somebody.
I have found a way to reproduce the noise too. If anyone is unsure of what the noise I am getting is, go drive down a washboard gravel road at about 50 km/h. It will make the same noise as I experience on a smooth highway at 120.
Now, I can tell you for sure that my noise is NOT caused by
Front wheel bearings, Rear wheel bearings, Tires, or Road noise.
I had my wife drive down the highway while I put my head to the floor all over the van. Tried as I might, I am not 100% certain where that noise is copming from.
I have always suspected the rear end. But figured changing the bearings would get rid of it. Well, $150 of new rear bearings and seals and its still making the noise.
I know at the local wrecker there is an AWD safari same year as mine with 240k on it that I could snag the whole rear end out of. But, what exactly could make the noise in there? I didnt notice any wear really at all on the outer ring while I had the drive shafts out. And all the gears looked ok. no metal shavings in the oil, or anything like that. the magnet is mostly clean.
Is there a diagnostic that can prove this is the problem? Bad gears? or, could it be the bearing that supports the pinion gear from the axle??
If its NOT the rear end, is it possible its a problem with the transfer case and its just carying the noise down the drove shaft to sound like its comeing more rom the rear end?
I am lost, and this is driving me absolutly insane.
Hopefully the OP can come back and confirm that his noise is the same as mine, and that a new rear end fixed it.