Selecting locks the transmission into the lowest possible gear, typically 1st gear . Purpose : To provide maximum torque and engine braking. When to Use :
: Most modern vehicles have protective systems to prevent shifting into these gears at dangerously high speeds, but you should generally slow down before manually downshifting to these modes to avoid excessive engine stress. Selecting locks the transmission into the lowest possible
: Climbing very steep hills where the car needs maximum pulling power. Selecting locks the transmission into the lowest possible