Remove dirt and wash the outside of the gearbox
Unscrew the oil filler and oil drain plugs and drain the oil from the gearbox, if this has not been done before.
Remove the clutch release bearing and foam ring 1 from the guide sleeve.
Remove the bolts and remove the rear engine mount with bracket, if this was not done when removing the gearbox from the vehicle.
Unscrew the reverse light switch with gasket.
Unscrew the bolt 1 fastening the stopper of the speedometer drive, remove the stopper 2 and the drive 3 of the speedometer.
Remove the breather.
Remove the four screws 1 and remove the shift lever housing 2 with gasket.
Remove the three bolts 1 and remove the input shaft bearing cover with the guide sleeve 2 of the clutch release bearing with seal.
Remove the reverse idler gear axle bolt on the front gearbox housing.
Remove the input shaft bearing snap ring if it needs to be replaced.
Be sure to remove the retaining large ring, otherwise do not separate the box.
Remove the ten bolts securing the front gearbox housing to the rear housing.
Disconnect the front and rear gearbox housings.
To do this, you can clamp the extension cord in a vice with soft pads on the jaws and hit with a copper hammer on the lugs with holes for attaching the front crankcase to the clutch housing.
Be careful not to tear the gasket.
Remove the adjusting rings from the seat under the front intermediate shaft bearing on the front gearbox housing, if they were installed.
Unscrew the two fastening bolts 1 and remove the plate 2 of the rod retainers with the gasket.
Remove the three retainer springs.
Set the 5th gear and reverse gear lever to the reverse gear position.
Remove the locking bolts securing the shift forks to the stems.
Mark the shift forks (their belonging to the stocks and orientation). Knock out the rods with a drift from a soft material and remove them.
The first to remove the stem 3 for engaging the 5th gear and reverse, the second stem 1 for engaging the 1st and 2nd gears, and the last stem 2 for engaging the 3rd and 4th gears.
When removing the 3rd and 4th gear shift rod, make sure that
so as not to lose the locking pin installed in the stem bore.
Remove the 1st and 2nd and 3rd and 4th shift forks from the synchronizer sliding sleeves.
Remove the retainer balls by substituting your hand and pushing them with a screwdriver through the holes inside the crankcase.
Remove the two stop plungers using a special tool or hooked wire.
If it is necessary to disassemble the 5th gear and reverse gear rod, then first unscrew the locking bolt 1, and then remove the head 2, the locking sleeve 3 and the spring 4 from the rod.
Remove the screw securing the reverse idler shaft on the rear gearbox housing.
Unclip the circlip of the secondary shaft rear bearing with pliers and, hitting the end with a soft material drift, press out the secondary shaft.
Simultaneously remove the output shaft assembly with the input shaft, the intermediate shaft and the axis of the reverse intermediate gear from the rear gearbox housing.
Check that the 3rd and 4th gear synchromesh is in neutral.
Disconnect the input and output shafts, paying attention to the fact that the loose rollers (14 pcs.) of the front output shaft bearing may fall out of the input shaft seat.
If during operation an oil leak from the gearbox through the oil seals is revealed, the defective oil seals must be pressed out.
Press two oil seals into the extension of the rear crankcase flush with the end of the extension, if they were removed. Their working edges should be directed inside the amplifier.
Install the mainshaft ball bearing circlip in the groove of the rear crankcase, if it was removed.
Set the 5th gear/reverse synchronizer sliding clutch on the output shaft to the reverse gear position.
Slide the input shaft onto the output shaft so that the bulk rollers do not fall out. At the same time, make sure that the protrusions of the blocking ring on the input shaft fit into the grooves of the synchronizer hub of the 3rd and 4th gears.
Connect the output shaft assembly with the primary one, with the gear set and the axis of the reverse idle gear, engaging the corresponding gears.
For the convenience of further installation, you can tie the resulting kit with a rope. You can tie the set with soft knitting wire, as shown in the picture.
Place the back of the crankcase vertically in a vise
Insert a set of shafts into the rear of the crankcase, open the retaining ring and press the ball bearings of the output shaft and gear assembly into the seats on the rear of the crankcase, applying force alternately to the end of the gear of the 1st gear of the output shaft and the end of the intermediate shaft until until the circlip compresses the outer ring of the ball bearing.
After that, carry out the final pressing until the retaining ring is seated simultaneously in the groove of the rear of the crankcase and in the groove of the bearing. (Figure 27 shows the circlip opening. The bolts are inserted so that the latches do not fall out. They can be removed so that they do not interfere).
Install the shaft of the reverse intermediate gear in the seat on the rear of the crankcase and tighten the mounting bolt without tightening it.
Install the rear of the gearbox housing in a horizontal position.
Insert the shift forks of the corresponding gears into the grooves of the sliding sleeves of the synchronizers.
Install the locking plungers between the holes for the 3rd and 4th, 1st and 2nd and 5th gears, and reverse gears.
For the installation of plungers, it is recommended to use a mandrel and a barb, but for this you will have to remove the plug and install a new one after installation. Therefore, it is easier to try to insert plungers without a mandrel.
Install the locking pin in the hole of the 3rd and 4th shift rod.
Install the 3rd and 4th shift rod into the crankcase bore and the 3rd and 4th shift fork head. Fix the fork on the stem with a locking bolt.
Install the 1st and 2nd shift rod into the crankcase bore and the 1st and 2nd shift fork head. Fix the fork on the stem with a locking bolt.
Install the lock plunger all the way into the 3rd and 4th shift shaft.
Assemble the 5th gear and reverse shift rod, if it has been disassembled.
Insert the stem into the hole in the crankcase and the hole for the 5th gear and reverse shift fork.
Fix the yoke to the stem with the locking bolt.
When mounting the stem, it is necessary to pay attention to the correct installation of the locking sleeve spring (one end must be inserted into the hole in the wall of the rear crankcase, and the other end must be inserted into the recess of the locking sleeve so that the tab of the locking sleeve is pressed against the head of the switching rod of the 5th gear and reverse).
Set the shift rod for 5th gear and reverse to neutral.
Install the balls and springs of the detents in the appropriate holes.
Install the stem retainer plate with gasket in place and tighten the two plate fixing bolts.
If, during the repair of the gearbox, either one of the gearbox housings or the gear block (or its parts) was replaced, then it is necessary to determine the size of the thickness of the adjusting rings 24 in order to provide the necessary axial clearance of the gear block.
After that, install a package of adjusting rings, selected according to the required thickness, into the seat of the ball bearing on the front of the crankcase.
Set the back of the crankcase with shafts in a vertical position in a vice.
Install the paronite pad.
Install the front of the crankcase, aligning the appropriate holes with the locating sleeves, and press it onto the ball bearings of the input shaft and gear train, hitting the lugs of the front of the crankcase with a soft metal hammer.
In this case, the input shaft must be pulled up.
Tighten the ten bolts securing the front and rear crankcases evenly diagonally to a torque of 14-18 Nm (1.4-1.8 kgcm).
It should be noted that the two upper bolts are longer (size M8-6gx35), the remaining eight bolts are M8-6gx30.
Install the circlip into the input shaft ball bearing groove.
If the input shaft oil seal was replaced, then it must be pressed into the bearing cover until it stops using a mandrel.
Install the bearing cover with gasket and tighten the three mounting bolts with a torque of 14-18 Nm (1.4-1.8 kgcm).
Insert the reverse idler gear axle bolt into the front crankcase and finally tighten both axle bolts to 44-56 Nm (4.4-5.6 kgcm).
Push the breather and the reverse light switch with gasket into the front crankcase.
Install the speedometer drive with a stopper in the crankcase and tighten the stopper fastening bolt.
Insert the oil filler plug.
Install the shift lever housing with gasket and tighten the four mounting bolts to a torque of 14-18 Nm (1.4-1.8 kgcm).
Lubricate the clutch release bearing guide bush with gear oil.
Install the foam pad on the guide bushing, pre-lubricating the bushing with gear oil.
Install the release bearing with clutch on the guide sleeve.
1. Before installing the front of the gearbox housing, you need to make sure that the forks are installed correctly.
To do this, we twist the gear shift housing onto two diagonal bolts. Look at the picture, the hull is set correctly. And we try how we turn on all the speeds.
When turned on, we twist the drive shaft a little. It is best to do this with an assistant.
2. When connecting the front and rear housings, do not forget to clean the mating surfaces from old gaskets, and coat them with a thin layer of sealant before connecting.
3. Plugs of the old sample and the new one (with crackers (inserts)) are interchangeable.
4. When tightening ten bolts of the body connection, you need to bait all the bolts, and then tighten them diagonally.
5. We install the cover of the gear lever without the lever itself. When installing, we shift a little “backward” so that the pin falls into place and moves the spring.
Then we install the lever itself and twist the cap by hand, before that we put a little Litol grease into the rocker mechanism.