So my car has this funky sound upon hard acceleration. its like a weird low pitch whistling or groaning. its pretty faint, but noticeable.

I just read about Billmans recommendation to re-torque the rear axle nuts and am bookmarking the article. could this weird groaning/low pitch whistle be the wheel bearing going out? or the hard acceleration straining the bearing? or could it be just simply that the bearing is moving around on the hub?

Ill try to get a video up on my way home and see if I can get the sound.

 

I had that sound which was most audible when turning from a stop, turned out to be my rear end. I drained the existing diff oil and replaced with some Redline and the sound went away permanently, until it grenaded a few years later

 

Yeah I would take a closer look at your differential