Gearbox - mechanical with manual shifting, has five forward gears and one reverse gear, all forward gears are synchronized
The body parts of the box - the clutch housing, the actual gearbox housing and the rear cover - are cast from an aluminum alloy and tied together with studs and nuts.
The joints are sealed with cardboard gaskets (sealant can be used for repairs).
To improve heat dissipation, the surface of the gearbox housing is ribbed.
The bottom of the crankcase is closed with a stamped steel cover with a gasket (mounted on studs).
The clutch housing is bolted to the engine block.
To ensure the alignment of the crankshaft of the engine and the input shaft of the gearbox, the crankcase is centered on two bushings (grooves are made under them in the mounting holes of the block and crankcase).
A third power unit support is installed on the rear cover of the gearbox.
It is attached to the crossbar, and the latter - to the floor of the body (on welded bolts).
- - first gear 3.67
- - second gear 2.10
- - third gear 1.36
- - fourth gear 1.00
- - fifth gear 0.82
- -reverse 3.53
In the gearbox crankcase, on the left side, there is a filler (control) hole, and a drain hole in the lower crankcase cover.
The holes are closed with tapered plugs.
There is a magnet in the drain plug.
It traps steel particles that get into the oil when parts wear.
A breather is screwed into the upper part of the clutch housing.
It prevents the increase in pressure in the gearbox when it heats up.
In the event of a breather malfunction (jamming of the cap), a strong oil leak through the seals is possible.
There are three shafts in the gearbox: primary, secondary and intermediate.
The input shaft is supported by two ball bearings located in the rear end of the crankshaft and in the front wall of the gearbox housing (the latter takes the bulk of the load).
A needle bearing is installed at the rear end of the input shaft, which is a days supporting the secondary shaft and ensuring the alignment of the shafts.
The output shaft also rests on a ball bearing in the rear wall of the gearbox housing and a roller bearing in its rear cover.
The intermediate shaft rotates in two bearings:
front - double-row ball is located in the front wall of the gearbox housing, rear - roller is located in its rear wall.
The input shaft has two gears.
The helical ring, located closer to the front wall of the crankcase, is in constant engagement with the front gear of the countershaft (thus these shafts always rotate together).
The spur gear of the input shaft is the crown of the IV gear synchronizer (when it is turned on, the torque is transmitted directly from the input shaft to the secondary, bypassing the intermediate one, therefore this gear is often called "direct").
The intermediate shaft is a block of four helical gears.
When any gear other than IV is engaged, the torque is transmitted to the secondary shaft through the intermediate one.
The gears of the intermediate shaft are located in the following order (from its front end): gear of constant engagement with the input shaft, gears of III, II and I gears.
A block of two gears is bolted to the rear end of the shaft: reverse gear (spur gear) and fifth gear (helical gear).
It additionally relies on a roller bearing in the rear cover of the gearbox.
The driven gears of III, II, I gears, reverse and fifth gears (in order, counting from the front end of the shaft) and synchronizers are located on the secondary shaft.
The driven gears of the forward gears are in constant mesh with the corresponding countershaft gears.
The gears of the 5th, 3rd and 2nd gears rotate on hardened journals of the secondary shaft, the gear of the first gear - on the bushing.
Involute splines are used to fix the reverse driven gear and the hubs of the fifth gear synchronizer clutch.
A circlip is installed on the output shaft, located between the synchronizer hub and the fifth gear driven gear.
At the same time with the helical gears of the forward gears, the gear rims of their synchronizers are made - spur gears of a smaller diameter.
They are directed towards the corresponding synchronizer (III, I, V - forward, II - back).
At the rear end of the secondary shaft, a flexible coupling flange is secured with a nut.
The synchronizer consists of a hub rigidly fixed to the output shaft, a sliding sleeve, a retaining ring, a blocking ring and a spring with a washer.
The hubs of the synchronizers of III-IV and I-II gears enter the grooves on the secondary shaft with internal projections, and the synchronizer hub at the gear is held by the same key as the reverse driven gear.
On the outer surface of the hubs there are slots along which the sliding sleeves move. The clutches have grooves that include the forks of the gearshift rods.
The locking rings are connected with their inner rims to the synchronizer rims of the corresponding gears and are pressed by springs towards the sliding clutches.
The springs rest on the side surface of the driven gears through washers.
Reverse gear does not have a synchronizer.
To turn it on, you need to engage the reverse idle gear with the driven gear of the output shaft and the drive gear of the gearbox.
The shaft of the reverse intermediate gear is attached to the rear wall of the gearbox housing.
The shift mechanism consists of a guide plate with eight rectangular cutouts in the center, upper and lower washers, a gear lever and its housing.
These parts are held together with three bolts.
The gear selector is attached with three studs to the rear cover of the box.
The neutral position of the lever between III and IV gears is set by two pairs of spring-loaded guide bars installed in the grooves of the guide plate and acting on the lower end of the lever.
The shift actuator consists of three rods connected to the forks. The forward gear forks fit into the grooves of the synchronizer sliding sleeves, and the reverse gear fork fits into the groove on the intermediate gear.
Inadvertent engagement of reverse gear instead of fifth gear is prevented by the lockout stop attached to the linkage yoke and the lockout pad attached to the shift lever upper housing.
Push the lever down to engage reverse gear, which lowers the lock stop below the lock pad.
Gearbox parts are splash lubricated.
The primary and secondary shafts are sealed with oil seals.