Bearing noise continues

[Shadowranger]

I hope this is the right forum.
Weeks ago I posted about wheel bearing noise and how darn loud it was. So, it was thought to be front wheel bearings. Now that they've been replaced (whole assembly) the noise continues. I asked the mechanic if there are bearings in the transfer case to which he said yes.
The noise at 30mph going downhill, coasting, is not there. On a flat road at 30-35mph it's a deep humming sound. When I let off the gas it goes away and when I press the gas again it comes back. And swerving at 30+ makes no discernible noise as someone suggested (wheel bearings).
Timing chain has been replaced a year ago, U joints are good but this noise bugs me..
Transfer case bearings?

 

[franklin2]

Exhaust system? Guts of your muffler rusted out? Has your cat been gutted? They make a annoying noise if the guts have been punched out.

 

[Shadowranger]

Exhaust system was replaced and in good shape.
I forgot to mention that in 4 hi the sound is still there.
Sounds like a driveline hum.
Can't get it in the shop for a while-they are backed up with work.

 

[franklin2]

Some noises you have to just monitor and see if they get louder. If they do, then they can be easier to find.

 

[bobbywalter]

could be bad body mount or contact

 

[sgtsandman]

If you have access to a lift, put the truck in drive on the lift and see if you can narrow down where the noise is comming from. A set of four jack stands works too, just way less comfortable and harder to move around under the truck. And because things happen, have a person in the driver's seat while doing it just incase things go wrong. Plus, they can put in and out of 4 HI, 4 LOW, and RWD while you are under there.

If it is only happening in 4X4, I would guess it is a transfer case issue but that is only a guess with the information given.

Sometimes stepping on the brakes will twist stuff around enough to replicate the conditions that the noise is happening at. You don't want the brakes engaged hard enough that the wheels won't turn. Just hard enough to make the driveline work and move.