Disassembly and repair of the gearbox is required for the following malfunctions
Increased noise in the gearbox:
- - wear of bearings;
- - wear of gear teeth and synchronizers;
- - axial movement of the shafts.
Difficulty shifting gears:
- - wear of the spherical joint of the gear shift lever, lack of lubrication in the assembly;
- - deformation of the gear shift lever;
- - burrs, bends, contamination of rod seats, jamming of locking blocks;
- - contamination of the splines of the sliding coupling and hub;
- - deformation of gear shift forks.
Spontaneous shutdown or unclear gear engagement:
- - wear of the holes for the balls on the rods, breakage of the clamp springs;
- - wear of the synchronizer blocking ring;
- - failure of the synchronizer spring;
- - wear of the teeth of the synchronizer coupling or synchronizer ring gear.
Low oil level or oil leak:
- - wear of the oil seals of the primary and secondary shafts;
- - loosening of the gearbox housing covers, damage to the sealing gaskets;
- - loosening the clutch housing to the gearbox housing.
The listed malfunctions may be caused by other reasons, the elimination of which does not require removing and disassembling the gearbox.
You will need: screwdrivers (two), replaceable heads “13”, “17”, extension, wrench, keys “10”, “13” (two), “17”, “19” , “30”, impact screwdriver, circlip puller, hammer, universal pullers.
Drain the oil from the gearbox, remove the fork and clutch release bearing.
Remove the flange of the elastic coupling from the toe of the secondary shaft and the reverse light switch
The gear selection mechanism can be removed from the vehicle without removing the gearbox. For clarity, we perform these operations with the gearbox removed.
Remove the cuff of the gear selection mechanism.
Set the gear shift lever to neutral
Using a 10mm socket, unscrew the three nuts securing the gear shift lever housing
Take out the gear selection mechanism.
The connection is sealed with a gasket
We look at the disassembly and assembly of the gear selection mechanism of the gearbox in the article - “Disassembling the gear selection mechanism of the gearbox.”
We install the gearbox with the clutch housing on the workbench. Using a 10mm socket, unscrew the ten nuts securing the lower gearbox cover.
Remove the cover
Remove the sealing gasket.
Screwdriver Through the hole in the gear selection mechanism, we move down the fork rod for selecting 1st–2nd gears (this engages 2nd gear).
Use a 13mm wrench to unscrew the rear cover fastening nut located inside the box body.
Using a 13mm wrench, unscrew the five nuts securing the back cover located outside the case.
We tap the cover bosses with a hammer, while using a screwdriver (or a suitable piece of pipe with the secondary shaft oil seal removed) hold the rear bearing on the secondary shaft.
Slide the cover off the studs and remove it, turning it clockwise (looking from the side of the secondary shaft shank) to prevent the cover from touching the rods and gear block of the 5th gear and reverse gear
Remove the cover gasket.
To replace the bearing of the gear block of the 5th gear and reverse gear, pry up the bearing rollers with a screwdriver and remove the rollers from the separator.
Remove the separator.
Hooking the outer ring of the bearing with a hook...
- remove it from the back cover slot.
Remove the thrust ring of the rear bearing of the secondary shaft.
Remove the outer ring of the bearing with the cage and rollers.
Remove the inner race of the bearing.
Remove the spacer sleeve
Remove the oil deflector washer
To stop the shafts from turning, you need to engage two gears. 2nd gear was engaged when removing the rear cover.
Before engaging reverse or V gear, release We are waiting for the fork to engage these gears.
To do this, use a 10mm wrench to unscrew the bolt securing the fork to the rod.
Press the fork down with a screwdriver and engage reverse gear.
Using a 17mm spanner (head) unscrew the bolt securing the fifth gear and reverse gear block.
Remove the bolt
Remove the gear block from the splines of the intermediate shaft.
Clamp the fifth gear and reverse gear block in a vice with soft metal jaw linings.
Using two screwdrivers, press the inner ring of the gear block bearing
Remove the inner ring.
Remove the 5th gear gear bushing
Remove the gear itself with the synchronizer blocking ring
Remove the hub
Remove the synchronizer clutch.
Turning the 5th gear and reverse fork on the rod towards the secondary shaft, remove the reverse gear intermediate gear.
Using a 13mm spanner, unscrew the two bolts securing the clamp cover.
Remove the cover and gasket.
We take out the springs of the clamps (the rod spring of the 5th gear and reverse gear is longer than the other two and has a dark coating color).
Use a magnetized screwdriver to remove all three latches.
Remove the rod and turn it on 5th gear and reverse with fork.
Remove the plug from the rod.
Using a magnetized screwdriver, remove the locking block from the hole in the gearbox housing, which is located between the crankcase sockets for the rods of 5th gear, reverse gear and 3rd–4th gears.
Remove the reverse driven gear from the secondary shaft
Remove the key from the shaft groove.
Using a 10mm socket, unscrew the bolt securing it to the 3rd-4th gear fork rod
Take out the rod.
A locking block is inserted into the hole of the rod, remove it.
Using a magnetized screwdriver, remove the locking block from the hole in the gearbox housing, which is located between the crankcase sockets for the rods of I–II and III and IV gears
(this cracker is noticeably longer than the cracker located between the shift rod for 5th gear - reverse gear and the shift rod for 3rd-4th gears).
Using a 10mm socket, unscrew the bolt securing the 1st-2nd gear shift fork.
Take out the rod.
Use an impact screwdriver with a Phillips head to unscrew the three screws securing the locking plate of the secondary shaft intermediate bearing
The screws are secured with special washers
Remove the locking plate
Using a 19mm wrench, unscrew the nut securing the reverse intermediate gear axle, holding the axle from turning with a 24mm wrench.
Remove the axis of the reverse intermediate gear.
By unscrewing the clutch housing mounting nuts, we separate the clutch housings and gearboxes.
Remove the gasket.
Remove the spring washer with a conical surface from the input shaft (its smaller diameter faces the bearing).
Clamp the splined part of the input shaft in a vice with soft metal jaw linings.
Use a 19mm spanner to unscrew the bolt of the clamping washer of the front intermediate shaft bearing.
Remove the bearing clamp washer.
Use two screwdrivers to pry the front double-row bearing of the intermediate shaft by the mounting ring
Remove the bearing.
When removing a bearing, its rear inner ring may remain on the shaft
Use two screwdrivers to press the rear inner ring of the bearing
- and remove it.
Remove the thrust ring of the rear bearing of the intermediate shaft.
Inserting a screwdriver between the ends of the bearing and the first gear gear of the intermediate shaft, we move the rear bearing.
Remove the outer ring of the bearing with the cage and rollers.
Remove the inner race of the bearing from the shaft toe.
By moving the intermediate shaft back...
- remove it from the gearbox housing.
Hooking the mounting ring with two screwdrivers rear input shaft bearing,...
- remove the input shaft assembly with bearing and synchronizer blocking ring
Remove the needle bearing from the front toe of the secondary shaft
Remove the shift forks for 1st and 2nd, 3rd and 4th gears.
Use two screwdrivers to pry the intermediate bearing of the secondary shaft by the mounting ring
- and remove it.
By tilting, we remove the secondary shaft assembly with gears, couplings, hubs and synchronizer blocking rings from the gearbox housing.
Assemble the gearbox in reverse order.
If, when removing the front double-row intermediate shaft bearing, its rear inner ring remains on the shaft, then the bearing must be assembled before installation.
To do this, carefully remove the separator with balls from the outer ring of the bearing using a screwdriver...
- and put it on the inner ring (removed from the shaft).
Insert the separator with balls and inner ring into the outer ring of the bearing
When assembling the input shaft, use a suitable piece of pipe to press the bearing onto the shaft, resting on its inner ring
After installing the secondary and intermediate shafts into the gearbox housing, we press in the front and rear bearings of the intermediate shaft, the intermediate bearing of the secondary shaft and the inner race of the gear block bearing.
We press the outer ring of the bearing of the fifth gear and reverse gears with a tool head of a suitable size (a piece of pipe) into the socket of the rear cover.
Insert the cage and rollers into the outer ring of the bearing.
To prevent the bolt securing the 5th gear and reverse gears from loosening, apply thread sealant to the bolt threads.
For ease of installation of the rear cover, we install the rear bearing assembly on the secondary shaft.
It is advisable to lubricate all sealing gaskets with a thin layer of silicone sealant.
When assembling the gear selection mechanism, apply Litol-24 lubricant to the ball joint.
For disassembly of the primary and secondary shafts, see the article - “Disassembling gearbox shafts.”
