Product review (4 stars): Don't Throw Away the Old Water Inlet Valve!
If your old water inlet valve is leaking, but does not whistle when filling, order the new valve assembly but keep the old one. When we replaced the old valve with the new one, the whistling was maddening!  I have heard of this happening with new washers as well. We swapped the bottom of the new assembly with the old one and the whistling - and leaking - was resolved. It may be due to a small soft rubber orifice in the bottom; this can easily fold over and further reduce the hole size. Make sure the diaphragms and pins on the top assembly seat correctly when doing the swap. Parts are interchangeable so, if you're handy, you can keep your washer dry and quiet for years to come.