No Reverse in Free-Wheeling

Randy, By design, Free-Wheeling prevents the car from backing up.  From the driver’s seat, take the engine as rotating in the POSITIVE direction.  Transmission input and output shafts turn in the same direction in all forward gears.  Without Free Wheeling, both transmission output shaft (T) and drive shaft (D) have the same positive rotational value (T = D).  In reverse, the transmission input and output shafts turn opposite to each other.

During normal driving, the transmission shafts remain locked together, so the engine can hold back the speed of then car. However, during Free-Wheeling, an “over-running clutch” allows the drive shaft to turn faster then the transmission output shaft. This over-running clutch effectively de-coupling transmission output shaft and drive shaft (T < D).  The transmission output and drive line are re-coupled when the engine increases the transmission shaft speed to match the drive shaft, allowing acceleration of the car. (T = D)

On the other hand, operating in reverse, the transmission output shaft rotates the opposite direction, providing negative rotation (-T). When the drive shaft stopped, it has zero rotation.  (D = 0), which still a larger positive value than the transmission output’s negative rotational speed. [D > (-T)]  Therefore, the transmission output shaft in reverse gear does turn, but that over-running clutch will not allow the car to back up.

I expect the function of the pin is to lock out the Free-Wheeling feature, locking the rotation of the transmission output shaft to the drive shaft and allowing negative rotational values for both transmission and drive shaft. Without a definite lock-out feature, Free-Wheeling may cause severe ‘white knuckle syndrome’ when going down steep hills.  Herb