So I had a 4:57 and Kaaz put together by rear end specialties. Now that it's back in the car, something seems not quite right. I did the break in procedure, but when accelerating and turning the rear end sounds like something is really loose. It almost seems like there is play in the differential or something. Everything seems fine when going in a straight line, or when turning but not on the gas. Does anybody think this is normal? Anybody else's do this?

I've got a race on Friday and...

 

Is the Kaaz broken in? What fluid did you use? And what backlash spec for the gears and pinion depth?

 

Sounds like the usual clutch chatter from a clutch-LSD. Even after proper break-in, the Mazdaspeed clutch-LSD in my miata did the same. Same thing happened to at least a couple other clutch-LSDs I know of. No matter how much break-in we did (we did A LOT), seemed like it'd still chatter until after some "real use". Try a different fluid or add friction modifier first and reduce its use the next fluid change. That's what I did and no more clutch-chatter.

EDIT: Want to add that the clunking feel could be horrifying. In my friend's case, it felt like he was dragging his driveshaft or exhaust on the pavement.