I have read most of the past posts on "dryer rumble"
Probably rollers or welded seam
My LG DLE2514W
dryer is a year old and has worked fine (small amount of rumble) for the last year.
Small amount of noise that I think it is normal.
We went on vacation to Texas for 5 months and once home I satrted it up and rumble galour. Another poster is right... it sounds like tennis shoes are in there.
We are remote and a serviceman with LG exp is 2 hours away.