This joystick controller sends digital signals to the transmission and hydraulic control units from the cab. It translates the operator's hand movements into electronic commands that govern forward speed, direction changes, and implement functions. A failing joystick produces erratic or unresponsive machine behavior, such as delayed gear engagement or unintended hydraulic valve activation. As an original component, its internal contact geometry and signal timing match the control unit's input logic, so no recalibration is needed after replacement.