Work vehicle and method for controlling work vehicle

A method for controlling a work vehicle, which includes:

• a power source,
• a hydraulic pump driven by the power source,
• a pump displacement control cylinder that controls a displacement of the hydraulic pump in accordance with a pressure of supplied hydraulic fluid and switches a discharge direction of the hydraulic fluid from the hydraulic pump in accordance with a supply direction of the supplied hydraulic fluid,
• a forward/reverse switching valve that switches the supply direction of the hydraulic fluid to the pump displacement control cylinder, and
• a pressure control valve that controls the hydraulic fluid supplied to the pump displacement control cylinder,
• the method comprising:
• detecting a vehicle speed of the work vehicle;
• receiving a command signal from a second operation device operated to switch between forward travel and reverse travel of the work vehicle;
• determining whether or not a shuttle shift operation is performed based on the vehicle speed of the work vehicle and the command signal from the second operation device;
• controlling the forward/reverse switching valve based on an operation amount of a first operation device operated by an operator to control the power source when it is determined that the shuttle shift operation is performed;
• and
• controlling the pressure control valve based on the operation amount of the first operation device when determining that the shuttle shift operation is performed.