Remove the back cover.
Remove the reverse gear pinion from the driven shaft (see fig. 180).
Fig. 180. Removing the tachometer drive.
1 - driven shaft reverse gear,
2 - tachometer drive gear,
3 - intermediate reverse gear,
4 - rod with fork for engaging reverse gear.
Remove the reverse intermediate gear shaft from the gearbox housing while holding the gear (see fig. 181).
[Material borrowed from an online resource: MERCEDESMAN]
Fig. 181. Removing the reverse intermediate gear shaft.
1 - intermediate reverse gear,
2 - reverse drive pinion,
3 - nut.
In gearboxes with reverse synchronizer, when removing the intermediate gear shaft, it is necessary to firmly hold the gear and synchronizer.
Loosen the nut on the rear end of the intermediate shaft and unscrew it. To prevent the shaft from turning, place a flange on the driven shaft and hold it with a wrench.
Use a puller to remove the reverse gear from the intermediate shaft.
When installing, do the following:
Place the reverse gear on the intermediate shaft and tighten the fastening nut. Lock the nut by pressing the nut flange into the groove of the intermediate shaft.
Install the reverse gear engagement fork into the groove of the reverse intermediate gear.
In gearboxes with a reverse 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 are directed towards the gearbox housing.
Install the reverse intermediate gear shaft into the crankcase with the flat side facing up.
Install the reverse gear pinion and the tachometer drive pinion on the driven shaft. The groove on the tachometer drive pinion should face rearward.
Install the gearbox rear cover mounting bolts and tighten.