When the tires are cold and hard, I've noticed a skip or two if you turn the wheel to full lock or close (kind of sounds like a thunk). This happens on my Corolla GTS (RWD) because it has a bunch of camber up front - so if it is what I'm thinking then it isn't the LSD, just the turning circle difference between the inner and outer tires. I don't know if that could be it or not but that's my thought.