My GE Profile dryer p/n DPSR473EWOWW makes a thumping noise when drum is turning

You are going to have to take it apart to find the problem. It could be the support rollers, idler pulley, or blower fan. What may have happened is that it is very dirty and the dirt and lack of lubrication caused problems. Clean it well and lubricate with white lithium grease, and replace the belt plus what is bad. Here is a color manual with detailed pictures: https://dl.dropbox.com/u/8010163/GEP...%20%281%29.pdf
I hope this helps.