where did the torque go?

[CanadianCamaro]

Last week after doing a burnout for my friend’s kid brother, I heard a metal clank come from the rear. At first I thought it was nothing more than something my tires picked up, but now I’m thinking it might be something worse. The reason I say this is that it feels like my car is not pulling like it use to. This might just be all in my head, but that clank did not sound good. Could my rear end be screwed up? The car still burns out fine in first and the tires still chirp hard in second – with a little kick in the pants, but it just feels like my bottom end isn’t what it was. I changed to a highflow cat and expected some loss down low, but not as much as this. Or is this all in my head. How do I find out for sure if it’s the rear end gone screwy?