Transmission gear shift system

A transmission gear shift system comprising a transmission case, a reverse shift fork supported on the transmission case in a circularly movable manner by a fulcrum pin, a shift rod for driving the reverse shift fork in an axially movable manner wherein the reverse shift fork is moved in a circular manner in one direction by movement of the shift rod from a neutral position to a reverse position, and a reverse idle gear is shifted from a neutral position to a reverse position by the reverse shift fork for establishing a reverse gear shift stage, wherein the reverse shift fork is moved in a circular manner in the other direction by movement of the shift rod from the reverse position to the neutral position and the reverse idle gear is shifted from the reverse position to the neutral position by the reverse shift fork to release the established reverse gear shift stage,

• a drive cam integrally formed with the shift rod, the drive cam having a first drive cam face for reverse shift, a second drive cam face for neutral return, a third driven cam face for reverse shift and a fourth driven cam face for neutral return, the third and fourth driven cam faces being provided on the reverse shift fork,
• wherein movement of the shift rod from the neutral position to the reverse position presses the first drive cam face for reverse shift of the drive cam against the third driven cam face for reverse shift of the reverse shift fork to move the reverse shift fork in a circular manner in the one direction, and movement of the shift rod from the reverse position to the neutral position presses the second drive cam face for neutral return of the drive cam against the fourth driven cam face for neutral return of the reverse shift fork, to move the reverse shift fork in a circular manner in the other direction.