i am little confused, i just got a 84 firebird axle with G code in the 8th position with disc brakes, but when i spin the wheels they turn in the opposite directions. so is it open or just bad posi unit? or did they make rear disc with open rear? the car did not have the rpo codes. i am thinking i bought a bad axle.

 

most likely its just open, yes plenty actually came with good gears like 3.73, disk brakes, and no posi. some buy those older 10 bolts and put in 28 spline axles and get a slp posi and you have ur self a pretty nice rear end.