On older style Maytag & Jenn Air dryers, the blower wheel often fails with age. The blower wheel connects to the motor and is the fan that blows the air through the dryer. When the blower wheel fails you will often hear a rumbling noise come from the dryer when you start it, and then again when you turn it off. Also you may start to notice the clothes taking longer to dry than normal since the blower wheel isn’t spinning as fast as it’s supposed to.
What goes bad on the blower wheel is the flat spot that is supposed to bed on the blower wheel. On a bad blower wheel the center will be round out.
(bad blower wheel)
On a good blower wheel the center will have a “D” shape with a flat spot for the motor shaft to grab onto.
(good blower wheel)