Shower valve

I have 2 Price Pfister tub/shower valves that rarely get used. I ran the water just to flow some water thru them and when I lifted the shower diverter the valves were very noisey. It is a high pitched squeal only when I divert to the shower head. What is the fix for this? Thanks! Jeff

noise

usually it means you have to clean the shower head.

The seal on the tub spout divertor has dried out and doesn't seal well. At least that is what used to happen on my shower. I have a different system now. It might resolve it if you replace the tub spout/divertor. I found that if I played with the divertor a little (push is down just a slight bit), it solved the problem until it eventually worked again after repeated wettings.