We have one of those newer washers that has no agitation blades in the center. What it does have is a narrow crevice at the bottom of the tub. That crevice can catch coins, and when one is just the right shape, it will cause a horrendous screech as part of the washing process engages.
That just happened and I found out part two of this problem; a coin can slip all the way down in the crevice where it can’t be seen and the only thing you can do is take a very skinny knife and slide it around, flipping the end upward every few inches of the circumference. It took a few trips around, but finally a worn penny arced up in the air.
Because this coin was hidden, I had to take out all the clothes to be able to do a full investigation. Usually, you can see the offender sticking an arc of his little round head up.
Gee, it was a fun time.