Yeah it's a wind up.

We tried a CIG diff in a Mazda Rotary for about half an hour, then went back to the workshop and took it out.

Too savage by half. Came out of a wet bitumen bend and stood on the throttle, followed by a 180 spin down the road. Great for getting the heart up near the throat. Good for traction...in a dead straight line. Difficult to drive quickly in the twisty bits with a peaky motor like the rotary.

HDT tried Detroit lockers briefly in their Toranas. It called for a different driving technique. Get it into a straight line before nailing the throttle.