85 cutlass 7.5 rear end question
 

I was out messing around with my carb earlier today when I decided to give my car a test run. I burned a little rubber & I got the same thing I usually get when burning some rubber which is this...
Attachment 797

When I did that I heard the drivers side give off a little chirp so I held my head out of the window & tried it again. This is what I got the second time.

Attachment 798


Does this mean the rear end in my car is a posi? If so, why doesn't it kick in every other time when I'm burning rubber?

It is possible for an open rear to do that. The only way you're going to know for sure will be to pull the cover.