how do i determine if my rear axle has a "posi ,sure grip, or any number of other names) in it without opening the axle cover or purposely trying tp spin the wheels (which is a terribly inaccurate way of testing) ? is there a tag on the axle, or a build sheet someplace i can find all the little things that make a difference? I HATE using profanity, but i am not sure how to say it without using it. "GM" (sorry!) has a sticker in the glove box with all the components. my Liberty does not have one. and I'm not sure if it should. but that type of information would be very handy.