Abstract: A synchronizer unit eliminates the chattering noise generated when shifting a manual transmission into reverse from a forward gear while the drive shaft continues to rotate in the direction corresponding with the forward gear by providing a reverse brake arrangement for arresting rotation of the input shaft. The reverse brake arrangement includes a shaft rotatably supported by the transmission housing and a clutch hub mounted on the shaft which is adapted to rotate with the shaft. The clutch hub has a splined outer circumference. A shift sleeve is provided for engagement with the splined outer circumference of the clutch hub and is movable in the axial direction of the shaft. The reverse brake mechanism further includes a frustoconical cone in coaxial relation to the shaft and disposed on a first side of the clutch hub. The frustoconical cone includes a frustoconical surface on its outer periphery. A first blocker ring is coaxially aligned with the shaft.

Abstract: A synchronizer unit eliminates the chattering noise generated when shifting a manual transmission into reverse from a forward gear while the drive shaft continues to rotate in the direction corresponding with the forward gear by providing a reverse brake arrangement for arresting rotation of the input shaft. The reverse brake arrangement includes a shaft rotatably supported by the transmission housing and a clutch hub mounted on the shaft which is adapted to rotate with the shaft. The clutch hub has a splined outer circumference. A shift sleeve is provided for engagement with the splined outer circumference of the clutch hub and is movable in the axial direction of the shaft. The reverse brake mechanism further includes a frustoconical cone in coaxial relation to the shaft and disposed on a first side of the clutch hub. The frustoconical cone includes a frustoconical surface on its outer periphery. A first blocker ring is coaxially aligned with the shaft.