2004 gmc seirra 1500 5.3L with quadrasteer growling from the rear?

I need help diagnosing what the hell is wrong just changed both rear hubs because I was told its probably bad bearings. Took a week to find the damn things because they're discontinued from every company and paid $400.00 for the both of them and low and behold didn't fix a damn thing....and I even said to the professional mechanic doesn't sound like wheel bearings to me I've already had the front ones go and know what they sound like the metal on metal grinding....but that's not what this was doing it sounds more like a growl or a rubbing and its only at slow speeds like real slow pulling into a parking space or parallel parking or actions like that. Could it be the axles themselves? I know one side is a cv joint for the quad steer but can't find a price on the axle shafts either because of course they've also been discontinued. Could it be the rear end its self (which wouldn't make sense to me because it doesn't do it all the time and I've heard the wind or whirring of a bad rear end and It's not even close to that sound. I don't even know how the process of changing the axle shafts themselves is gonna be if I can even find them. And help from any gm tech or mechanic that's been thru what I'm going thru now would be great.