Find out about the auto-gear extension. It uses the same lever asthe emergency gear extension. When on, the gear will free fall if IAS drops below a certain value - typically close to or even faster speed than Vx or Vy. It uses the pitot head located near the pilot's side window.
This has ramifications for short field performance or go-arounds since the low speed means that the gear stays extended even though you have selected it up.
It can be selected off. There may have been an advisory notice or even an AD to disable it.