Tring to pin point this high pitched howl at 55mph... tell me what you think. I've replaced the driverside half shaft. Soon when the $ is avl. I'll do the passanger side shaft..

 

Mine has a similar sound, to me its the whine of gears in the diff. Since the fluid is not heavy like a trucks diff lube. I have a real good set of dj headphones on to listen on it a few times. Did it get more quiet after you replaced with a new 1/2 shaft?