RainSoft Gold Series Water Softener

Our RainSoft Gold Series Water Softener has been making a high whining sound and there is a constant yet small amount of water steadily flowing from the drainage hose.

I shut the bypass valve to (hopefully) stop the flow of water through the drainage hose, but water immediately began to leak from the left bypass valve itself. So I reopened the bypass. In the open position there is no leak from the bypass system.

Should I shut off the water at the main and clean the valve or do I need to replace the bypass valve system?

Is that something easy enough to do myself?

We all know what it's like dealing directly with the RainSoft people.