Rear end on '85 Trans Am?

[trans_am]

What kind of gears does this car have? Does it have posi traction?

[Lyle A]

Here are some Specs. (http://www.phy.duke.edu/~hartley/iroc/iroc_specs.html) You really need the RPO code for the rear end to tell. They may still exist on a label on the door or in the glove box.