Synchronizers

Synchronizers
The low speed synchronizer is mounted on the main shaft and will engage with either the main shaft first or the main shaft second gear. The high speed synchronizer is also mounted on the main shaft and will engage with either the main shaft third or the input shaft fourth gear. The reverse synchronizer is mounted on the main shaft and engages with the main shaft fifth or the main shaft reverse gear. The countershaft meshes with the main shaft to produce the appropriate gear ratio output.







Internal Gear Components

Gearshift Controls





Gear Control Lever





Gear Shift Lever Operation
Gear selection is transmitted from the gearshift control lever (8) into the gearshift lever case (6) located at the rear of the transmission. The gearshift lever case (6) contains a gearshift arm (9), a reverse gearshift limit yoke (5), and a gearshift lever (4). These three components are attached to the gearshift shaft (7). The gearshift control lever (8) is fitted into the gearshift arm (9). When the gearshift control lever (8) is moved, the gearshift arm (9), the gearshift shaft (7) and the gearshift lever (4) are moved forward, backward, left or right, depending upon the gear selected.





Gear Shift Lever Components





Reverse Gearshift Limit Yoke
The reverse gearshift limit yoke (5) is located in the gearshift lever case and rides on the gearshift shaft. The reverse gearshift limit yoke prevents the transmission from being shifted directly from fifth gear (1) to reverse. When the transmission shifts into 5th gear, the gearshift limit spring (4) turns the gearshift limit yoke clockwise causing the reverse gearshift limit yoke to land on the reverse gearshift limit bolt (3). This action prevents a 5th -to-reverse gearshift.





Shifting from 5th gear (2) to neutral (1) is possible with the reverse gear shift still canceled. This is due to the reverse gearshift limit yoke (5) making contact with the reverse gearshift limit bolt (3) preventing further gearshift control lever (6) rearward movement.





When the gearshift shaft is turned to the neutral position between 3rd and 4th gears (1), the gearshift limit spring turns the reverse gearshift limit yoke (6) counter-clockwise away from the reverse gearshift limit bolt (2). This action cancels the limiting mechanism and allows a reverse gearshift.
After the reverse gearshift limiting mechanism has been canceled, reverse gear is then available.