Unplug the dryer and shut off the gas if it is gas. On the back side of the dryer there will be a bunch of screws to remove the whole back sheet metal and more to remove the back of the dry lent duct. The lower part covers the fan. This is probably where the ufo is making the noise. This is a good time to clean out all the lent in the duct, vent, fan and around the total inside. I do this at least once a year. Makes it less chance of a fire and dries better. Clean it all the way to the outside of the house. Hope thgis helps.