I have a Whirlpool Dryer Old School from around 2004. It had a slight squeaking several months ago so I replaced the belt and 2 rollers with Whirlpool parts and the squeak upon startup went away. Now I hear a slight thump every rotation when it’s empty. Took it apart and didn’t see anything wrong to cause it. Now when the motor is running, it makes the noise, but when I turn it by hand from the inside the drum, the noise isn’t there. What do you guys think it could be?