I notcie every once and a while when I lose tracion( Slippery roads, Hard accel,ect) I funny noise comes from the readend nad only one wheel would spin. I noticed with when I got stuck in snow. Its only once and a while. I dunno when that last time the rearend oil was changed. Could that be the problem??or do I need a new rearend??

 

Jack up the rear end. The first thing to do is put the car in neutral and spin the rear tires. Do they both spin in the same direction? Next, get a friend to hold a wheel, a torque wrench, and a socket to fit a lug nut. Use the torque wrench on a lug to spin the tire, you should have to put, I believe its 35 ft-lbs of torque to spin the tire w/ your friend holding the other one if memory serves anyways. If it is significantly less, you got a bad posi. The posi should only slip when there is enough difference in torque between the wheels that you'd probably be turning. Anyways check that out and post how much torque it takes to break the thing loose, and then post back in here, I'm sure a numbers guru will have the correct torque spec, and who knows, maybe I am right about that spec lol

 

after that test, if it checks out ok..

it wouldnt be a bad idea to do a rear end fluid change and dont forget to add the posi additive... and see if that helps.