I've got a GE washing machine that's 4 maybe 5 years old.

This morning when I left I started a load of laundry. This afternoon when I got home I had to swim down my hallway.

It seems that it won't stop filling. It drains ok I've checked that. It fills just fine, I've checked that. But, for some reason, it just keeps on filling, it doesn't seem to stop. This machine is totally sealed and I don't really want to take off the casing unless it's absolutely necessary. Is there some sort of switch or thingamabob that is no longer being triggered when the washer is full?

I've never had any problems with it before. It does get a good bit of use, at least 6 loads a week, more in the summer.

Thanks in advance.