2000 ws6 TRANS AM REAR END NOISE?????

Hey fellas, been awhile since I've been here. I've got a new problem, this time with the 2000 Trans am ws6 rear end. The rear end is making noise like a grinding sound. I brought it to service station and had them change the fluid (synthetic). The rear end still makes noise and it seems to be getting worse. The guy who changed it never took off the cover to inspect he just "sucked" old crap out and put in new. I'm guessing he put in the additive but wasn't sure so I took some some fluid out and added some limited slip-posi additive. The car still makes noise. I jacked the car up and spun the wheels and they don't spin in the same direction, they spin opposite of each other. what does this mean? Does this mean my posi is shot? I'm pretty sure that this car came with a 3.23 ratio and posi. Anyone have any insight? Ineed to sell this car help!

if you have the traction control system you probably don't have a posi-trac. the computer would control the wheel spin. sounds like a bad ring gear/pinion or a bad wheel bearing. **)

Really, I thought it was a posi trac setup. It does have traction the control system. How can I check for either of these conditions? When I jack the wheels up and spin the tires they do spin the opposite way and it does make a grinding sound. I notice some play in the wheels when I pull back on them. Any other insight? This is my wifes ride and she doesn't beat on it or race. It only has 68800 miles on it.

a bad wheel bearing noise would be steady most of the time. a ring/gear normally makes a noise pulling or coasting., but not both. if the wheels are turning in opposite directions then its not posi-trac. if you have traction control you don't want posi-trac. you need to get it to a shop that known what hes doing. **)

Then it must be a wheel bearing because it makes noise all the time. Thanks for the help.