They changed the composition of the drum rollers to make them less susceptible to "flat-spotting". Does the dryer make the noise when it is warm? If no noise when warm you will need to change the drum rollers. If the noise continues when warm the drum weld is probably cracked and you will either need to replace the drum or have it welded by an expert TIG weldor who is used to working on very fine gauge materials. I assume you have inspected the belt for any defects.