My washer has been causing overflow in the drain pipe. We used a Drain King on the pipe and ran a hose full blast down the pipe afterwards with no overflow problems. But when the washer drains, it continues to overflow. Having ruled out the drain pipe being the issue, I can only imagine that there is a drain sensor or the drain pump that is no longer inhibiting the flow to a rate that the pipe should be able to handle without overflowing. Thoughts?