What you describe sounds like a bad wheel bearing, often associated with a growling noise or possible cupped front tires that howl. I have seen brand new out of the box bearings be bad as well as some take a dump shortly after being installed. Also, how does the tire wear look? Cupping will often times present with howling/vibration and will change with speed.
He said he's swapped tires. I changed my hub on my driver side and it is howling already, its tight and smooth though so **** it.
You just gonna run it? Upon further digging I think it must be these hubs. ****ing new GM JUNK!! Things both have under 500 miles. Oh well warranty.
Updating this. Re and re P.S wheel hub again (10,000 miles max) and all is good now.