strange noise at 30mph+

Sorry but I am at a loss for ideas. I started to hear a buzzing/strange noise when I got up over 30mph. I was thinking that my T-case chain was stretching out. the other day it got a lot louder. The sound seems to be coming from my shift lever area. I threw it in 4Hi and I could clearly make out the sound my T-case makes. I don't think that is it. I rolled down the window and it might be my axle. I can't recreate the sound unless I am going over 30mph. If I start to slow down it goes away even if I am still over 30mph. It does not sound like my brakes. I pulled off my tire and checked the brakes and I checked for play in the hub.
As you can see I am all over the place. I usually have a 2nd person to help my diagnose things but at the moment I am running solo. Any ideas you can throw at me would be awesome. I at a loss on what to check.
1999 Cherokee 4.0

does it change when you steer left or right?
usually a hub will change pitch when you're turning.

you may want to pull the front driveshaft for troubleshooting purposes. When the double cardan at the top goes they tend to make grinding noises and vibrations.

87manche said:

does it change when you steer left or right?
usually a hub will change pitch when you're turning.

you may want to pull the front driveshaft for troubleshooting purposes. When the double cardan at the top goes they tend to make grinding noises and vibrations.

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I have not noticed it when I turn left or right because I slow down below 30mph when I turn. I will pull the driveshaft tonight. Thanks for the idea.

Just removed the driveshaft and took it for a spin. No vibration. Now to rebuild it. Thank you.