Rear end ckunking on left turn

[meric42]

I have a '57 Sunliner and rebuilt the 9" differential about two years ago using a good used ring and pinion along with all new bearings and clutch plates and have only put less than 200 miles on it. It has now developed a clunking when turning left. I have read that this can possibly be caused by a faulty axle bearing or needing friction modifier. I used specific LSD oil when I assembled and filled the Diff. I would be interested to hear the thoughts from those more experienced than myself to help solve this problem. Thanks in advance