So they can blame your carrier just to get off the phone with you and move on to the next caller they also don't intend to help. I mean, call I guess, maybe you'll get luckier than I did.
Supposedly the carrier wears down where the side gears ride, and excessive wear here will result in the locker being too loose. That's the explanation given to me by powertrax customer service when their lock right was too loose in a Dana carrier with about 5000 miles on it.
I threw their junk back in the box and returned it, went with a Torq which went in with perfect clearances and has worked flawlessly. I found it super interesting that the Torq and Aussie both stacked up some thou thicker than the Lock right such that it made up exactly for the extra slack but the rep on the phone wouldn't even entertain the idea that their part could be out of spec.