We install the gearbox on a special stand or workbench with the back cover up

With a 13 head, unscrew the three bolts securing the rear cover (Fig. 1).

JH3 Transmission Disassembly

Remove the cover.

The cover must be removed carefully along the horizontal axis of the box, since the cover has a lubrication tube that enters the input shaft hole.

JH3 Transmission Disassembly

Using a 27 head, unscrew the nut securing the fifth and reverse gear block gear (Fig. 2)

JH3 Transmission Disassembly

Using pliers, remove the lock washer (Fig. 3)

JH3 Transmission Disassembly

Using a drift (you can use the old valve) and a hammer, we knock out the fifth gear fork fastening pin (Fig. 4)

Using a puller, we remove the fifth gear along with the fork.

JH3 Transmission Disassembly

If there is no puller, you can use two powerful screwdrivers (Fig. 5)

JH3 Transmission Disassembly

Remove the plug (Fig. 6)

JH3 Transmission Disassembly

JH3 Transmission Disassembly

We remove the spacer washer (Fig. 7) (when removing the washer, you need to remember its position so as not to confuse it during assembly, the eighth figure shows the correct position of the washer)

JH3 Transmission Disassembly

Using the internal torxE-16 head, unscrew the bolt of the rear end of the secondary shaft (Fig. 9)

Removing the fifth gear: 1 - reverse light switch

We remove the fifth gear with a three-finger puller or with B.Vi tools. 22.01 and B.Vi. 1000-01 (see fig. 10).

If there is no puller, you can use two powerful slotted screwdrivers, having previously screwed the bolt onto the rear end of the secondary shaft.

JH3 Transmission Disassembly

With a screwdriver, the assistant rests against the end of the gear, and with not strong blows on the bolt we compress the gear (Fig. 11).

JH3 Transmission Disassembly

Using a TorxE-12 head (in some cases TorxE-14), unscrew 16 bolts securing the gearbox housing to the clutch housing (Fig. 12).

Five bolts are located inside the clutch housing.

JH3 Transmission Disassembly

Before disconnecting the crankcase, you need to attach the magnet to the fork stem so as not to lose the balls and springs of the retainers (Fig. 13)

JH3 Transmission Disassembly

We insert a thin slotted screwdriver between the thickened tides of the crankcases, and disconnect the gearbox crankcase with a hammer (Fig. 14).

The crankcase is sealed with a sealant adhesive.

JH3 Transmission Disassembly

After disconnecting the crankcases, we remove the three springs and three retainer balls. View of the spring and ball in Figure 15.

JH3 Transmission Disassembly

We remove the magnet installed in the gearbox (Fig. 16).

On the magnet you can see the wear chips of gearbox parts.

JH3 Transmission Disassembly

We knock out the pin of III and IV gears (Fig. 17)

JH3 Transmission Disassembly

And remove the stem along with the plug (Fig. 18)

JH3 Transmission Disassembly

Remove the retaining balls from the technological holes shown in Figure 19.

JH3 Transmission Disassembly

After that, we take out the secondary shaft (Fig. 20)

JH3 Transmission Disassembly

With a beard we knock out the pin from the reverse gear fork (Fig. 21)

JH3 Transmission Disassembly

Remove the input shaft and reverse clutch (Fig. 22)

After that, we wash all the parts and inspect the bearings.

If there are signs of wear, then the parts are replaced. We prepare all the details for assembling the gearbox.

Gearbox assembly will be discussed in the next article.