DOH, thanks MartyE; saw the Aux on the LCD and have successfully turned off the forced coupler sounds using the manuals instructions.
I use whistle sound #5 and now its seems louder above all the other sounds. I have been waiting for this whistle sound since I started into Lionel in 2014; as a kid I had a bedroom window facing the railroad tracks (1 mile away) in my Pennsylvania coal town and at night I could easily hear the locos going by with, I think, this whistle.