Gearshift Mechanism

The gearshift mechanism consists of the shift lever housing, shift lever and linkages and two selector cables, each connected to its lever on the transmission.

When the shift lever is moved sideways, a link plate (36) on the outside of the housing converts this movement to a pull/push movement of the cable (37). If the lever is moved backwards or forwards, on the other hand, the lower link rod (39) actuates the other cable (38) directly.

The lateral lever (40) operates a selector spindle (41) with an actuator disc (42) on the other end. This is spring-loaded, and tries to return the shift lever to the 3rd/4th gate when no gear is engaged. To maintain the selected gear position, there is also a spring loaded ball (43) which runs in radial grooves around the selector spindle.

The forwards/backwards lever arm (44) in attached to a shaft with a selector lever arm (45), which in turn acts on a tubular actuator (33), which also houses the selector spindle. Attached to the actuator disc end of the actuator (33) is a selector arm (32) which operates the selector fork (26), selector lug (34) and pivot arm (35) for the different gears. These in turn move the selector forks and hence the synchromesh sleeves for the different gears.

When the shift lever is moved sideways, the actuator disc (42) moves the selector arm (32) to the right position; when the shift lever is moved backwards or forwards, the selector lever (45) operates the actuator (33) and hence the selector arm (32), thereby moving the selector fork.

Connected to the actuator disc, there is a spring loaded reverse gear interlock (46)which prevents reverse gear being selected accidentally when changing down from 5GR.
- The reverse gear interlock (46) is spring-loaded and normally rests on a lug on the actuator disc (42).
- When the shift lever is moved sideways towards the 5th/reverse gate, the actuator disc rotates so that the reverse gear interlock no longer rests on the lug, and presses against the tubular actuator (33) instead.

When the shift lever moves up into 5th position, the tubular actuator moves sideways, allowing the reverse gear interlock to drop onto the selector rod (41) behind the actuator, preventing the actuator returning directly from 5th to reverse position.

Before engaging reverse, the shift lever must return to neutral, allowing the actuator lug to lift the reverse gear interlock.

Only then can the actuator move to the reverse position.
This arrangement eliminates the need for a reverse gear interlock device in the shift lever housing.

When engaging 1GR, for example, the sequence of events is as follows:
When the shift lever is moved sideways to the 1st/2nd gate, the shift lever pivot arm produces a pulling movement in the sideways cable, so the cable turns the selector spindle and actuator disc. This movement also rotates the tubular actuator, bringing the selector arm into line with the 1st/2nd gear pivot arm. At the same time, the actuator disc locks the 5th/reverse selector fork and 3rd/4th engagement lug, preventing two gears from being engaged simultaneously.

Moving the shift lever forwards towards 1GR pulls on the cable which rotates the forwards/backwards pivot arm. The selector lever now moves the tubular actuator and selector arm sideways, moving the 1st/2nd gear pivot arm in the same direction. The pivot arm then moves the selector fork in the opposite direction, causing the synchromesh sleeve to engage with the 1st gearwheel.

The sequence of events is similar when the other gears are selected. The actuator disc moves the selector arm to the position for the gear to be selected, after which the tubular actuator moves the appropriate selector fork sideways, either directly (5th/reverse) or indirectly (other gears).

The selector components inside the transmission have ball bearings and sliding bearings lubricated by the transmission oil.