I agree with Jim. The only time I hear the screech is when turning the knob when not in the seat for stationary pto use and that quits in a few seconds, or if I hit a big bump or sometimes when I turn in the seat to look back. Your seat switch may be too sensitive for your body weight.Welcome to this forum
My guess is operator presence(seat) switch is malfunctioning. My M7040 only makes an audible noise(screeching) sound when pto lever is engaged with no operator sitting in tractor seat or when operator raises out of seat with pto operating