rear driveline issue

[g_man668]

i recently had my rear diff go on her way out, lots of big shavings and everything in the fluid and whatnot howling/grinding when off the throttle, pulled a used axle out of an 05 (my rig is an 06) both were 3.73 single rears with LS i swapped in the "new" axle the other day the off the throttle noise is gone but now i have a bit of a rubbing/grinding feel fairly faint until about 30 km/h then after that it just switches to a high pitched howl but is not load dependant its road speed dependant.. any thoughts? we checked the diff out before we put the axle in everything seemed fine, running Lucas 75w140 Synthetic diff oil in the new axle.. sound like a blown diff from the Wreckers? or possibly a bad rear wheel bearing? one thing i noticed is when we spun the wheels with the tires jacked up both span in the same direction which is odd because when they are LS doesn't the opposite wheel you are spinning spin the opposite direction? sorry about the lengthy post i'm new to the site and i'm leaving to the coast on Sunday for a Excavator Course