Product review (5 stars): After changing rollers twice and still having a thumping noise ...
After changing rollers twice and still having a thumping noise, I did a little more research and discovered that LG had a problem with the drum seam splitting.  Figured I'd  pull it apart one more time and install new drum. That was the answer.  Item arrived promptly before schedule and was installed with no problems. Have been using dryer over 2 weeks and it is still running quietly.