howling noise

[KeelesKustome]

It's raining pretty good today, I went out and did a pull from 2nd to redline getting a wet condition log. Less then 20 seconds later a loud howling noise began and it sounded like it was below the floor pan. My first thoughts were the transferr case. It has fluid and it isn't burnt. My only belt is alternator, and this didn't sound like that, I stopped for 2 minutes let it idle and drove home, on the way i puched it and had not lost boost, telling me it wasn't the turbo. By the time I got home it began to howl again, pinpointing the howling was verry difficult as it revirbirated through the cabin. I was thinking hydrolock, but it idles fine, could it be my transmission pump?

Just went out for another drive, the sound didn't happen except for a millasecond when i was on a curve. It's not effecting drivability when it happens.
It's just verry loud, like pulling a loaded pallett across smooth concrete type howl, and it revirberates in the cab.

 

[TrevorS]

Any chance it's coming from the differential?

 

[KeelesKustome]

possibly, it's so hard to tell, when it happns, 'll check for burnt fluid.