I have a Kitchen Aid brand trash compactor which I am told is made by Whirlpool. I recently order a new knob (part # 9871799) from your company because the last knob broke in half when I turned on the compactor. When I tried to install the new knob I cannot get it to stay in place in the off position. When I turn the compactor on the knob locks in but as soon as it goes back to off the knob can just fall out. This was not the case with the original knob, what am I missing or doing wrong on this installation?

I compared the new knob to the original one and I have the correct part. Is there a retaining clip of any type to keep the knob in place?