The Mustang's three-speed shifter is simple in scope and operation. The shifter handle moves the spring-loaded selector shaft from right to left depending on which side of the H-pattern you're seeking. A tang, or straight shaft, pressed into the selector shaft moves shifter levers and rods fore and aft to engage First and Reverse when the inboard lever is tanged. When the outboard (left) shifter lever is tanged, we have Second and Third gear. The inboard lever moves the First/Reverse rod while the outboard lever moves Second and Third.