Anyone running a wavetrac lsd?

Anyone out there running a wavetrac lsd?

I have had mine for 500 miles and it pulls like a train, but it clunks when i put it in reverse just as it starts to move. With the engine off in gear, if I rock the car the l/h drive cup moves in and out by about 1/8th inch.

I've taken the box back out as I was worried the preload was off but the lsd is firm with no side movement and the correct turning torque.

I'm wondering if this is due to the ramps and Belleville washers inside but need to be sure before I put it back in.  There is the option to get it looked at by a professional if no one else has had this.

Cheers

Adam