Remove back cover.
Remove the reverse gear from the driven shaft (see fig. 180).
Pic. 180. Dismantling the tachometer drive.
1 - reverse gear of the driven shaft,
2 - tachometer drive gear,
3 - intermediate reverse gear,
4 - a rod with a reverse gear engagement fork.
Remove the shaft of the intermediate reverse gear from the gearbox housing while holding the gear (see fig. 181).
Pic. 181. Removing the reverse gear shaft.
1 - intermediate reverse gear,
2 - reverse drive gear,
3 - nut.
In gearboxes with a reverse synchronizer, when removing the intermediate gear shaft, it is necessary to firmly hold the gear and synchronizer.
Loosen the nut at the rear end of the intermediate shaft and unscrew it. To prevent the shaft from turning, put a flange on the driven shaft and hold it with a wrench.
Remove the reverse gear from the intermediate shaft with a puller.
When installing, do the following:
Put the reverse gear on the intermediate shaft and tighten the fastening nut. Lock the nut by pushing the collar of the nut into the groove of the intermediate shaft.
Install the reverse gear fork into the groove of the reverse idler gear.
In gearboxes with a reverse gear synchronizer, install the reverse intermediate gear together with the synchronizer so that the protrusions on the synchronizer ring and holder are directed towards the intermediate shaft bearing.
When installing the reverse intermediate gear, make sure that the bevels on the gear teeth point towards the gearbox housing.
Install the reverse idle gear shaft into the crankcase with the flat facing up.
Install the reverse gear and tachometer drive gear onto the output shaft. The groove on the tachometer drive gear must be facing backwards.
Install the gearbox rear cover bolts and tighten.