1 - input shaft; 2 – an epiploon of a primary shaft; 3 - clutch housing; 4 - spring washer; 5 - breather; 6 – the needle bearing of a secondary shaft; 7 – a ring gear of the synchronizer of IV transfer; 8 - shift fork III and IV gears; 9 - sliding clutch of the synchronizer of III and IV gears; 10 – a hub of the coupling of the synchronizer of III and IV transfers; 11 – a gear wheel and a ring gear of the synchronizer of III transfer; 12 – a gear wheel and a ring gear of the synchronizer of the II transfer; 13 - shift fork I and II gears; 14 - clutch switching I and II gears; 15 - gear and ring gear of the synchronizer of the 1st gear; 16 - intermediate bearing of the secondary shaft; 17 - gear V transmission; 18 - gear lever; 19 – the case of the lever of a gear change; 20 - spacer sleeve; 21 – flexible coupling flange; 22 - secondary shaft; 23 – an epiploon of the back bearing of a secondary shaft; 24 - rear bearing of the secondary shaft; 25 - oil deflector washer; 26 - bearing of the gear block of V gear and reverse gear; 27 - block gears V transmission and reverse; 28 - synchronizer hub V transmission; 29 - intermediate reverse gear; 30 - back cover; 31 - rear bearing of the intermediate shaft; 32 - sliding clutch of the synchronizer of I and II gears; 33 - filler plug; 34 - intermediate shaft; 35 - front bearing of the intermediate shaft; 36 - gearbox housing; 37 - rear bearing of the input shaft; 38 - guide bushing.
The gearbox is mechanical, with manual shifting, has five forward gears and one reverse gear, all forward gears are synchronized. It is unified with gearbox 2107; only the back cover differs slightly: the hole for the speedometer drive is closed with a plug, since the speedometer «fields» driven from the transfer box. Currently, all gearboxes use the 2105 transmission range.
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. Connections are sealed with cardboard gaskets (when repairing, you can use a sealant). To improve heat dissipation, the surface of the gearbox housing is ribbed. From below the crankcase is closed with a stamped steel cover with a gasket (fastening - on studs). The clutch housing is bolted to the engine block. To ensure the alignment of the crankshaft and the input shaft of the gearbox, the crankcase is centered on two bushings (under them, grooves are made in the mounting holes of the block and crankcase). A third support of the power unit is installed on the rear cover of the gearbox. It is attached to the cross member, and the latter to the floor of the body (on welded bolts).
In the gearbox housing on the left side there is a filler (control) hole, in its bottom cover - drain. The holes are closed with taper threaded plugs. There is a magnet in the drain plug. It traps steel particles that enter the oil when parts are worn. A breather is screwed into the upper part of the clutch housing. It prevents the increase in pressure in the gearbox when it is heated. In the event of a breather failure (cap jamming) severe oil leakage through the seals is possible.
There are three shafts in the gearbox: primary, secondary and intermediate. The input shaft rests on two ball bearings - 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 the front support of the secondary shaft and ensures 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: the front one is a double-row ball bearing, located in the front wall of the gearbox housing, the rear one is roller, located in its rear wall. Through the reverse gear and V gear, the intermediate shaft also rests on a roller bearing in the rear cover of the gearbox. On the rear wall of the crankcase, the axis of the intermediate reverse gear is also fixed.
The input shaft has two toothed rims. The helical ring, located closer to the front wall of the crankcase, is in constant engagement with the front gear of the intermediate shaft (so these shafts always rotate together). The spur crown of the input shaft is the crown of the synchronizer of the IV gear (when it is turned on, the torque is transmitted directly from the input shaft to the secondary, bypassing the intermediate one, therefore this transmission is often called «straight»).
The intermediate shaft is a block of four helical gears. When you turn on any gear other than IV, the torque is transmitted to the secondary shaft through the intermediate. The gears of the intermediate shaft are located in the following order (from its front end): gear wheel of constant engagement with the input shaft, gears of III, II, I gears. A block of two gears is bolted to the rear end of the shaft: reverse (spur) and V gears (helical). It additionally relies on a roller bearing in the rear cover of the gearbox.
Driven gears of III, II, I gears, reverse and V gears are located on the secondary shaft (in order, counting from the front end of the shaft) and synchronizers. The driven gears of the forward gears are in constant engagement with the corresponding gears of the countershaft. Gears of III and II gears rotate on hardened necks of the secondary shaft, gears of I and V gears - on bushings. The driven reverse gear is rigidly fixed on the shaft with a key. At the same time with the helical gears of the forward gears, the 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 flange of an elastic coupling is fixed with a nut. Previously, the nut was fixed from unscrewing by a lock washer placed under it - its edges were bent on the edge of the nut. Now an anaerobic sealant is applied to the threads, and the washer is not installed.
The synchronizer consists of a hub rigidly fixed to the secondary shaft, a sliding clutch, 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 hub of the synchronizer of the V gear is held by the same key as the reverse driven gear. On the outer surface of the hubs there are slots along which sliding couplings move. The couplings 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.
The reverse gear does not have a synchronizer. To turn it on, you need to enter the intermediate gear into engagement with the driven gear of the output shaft and with the reverse drive gear in the rear gear block on the intermediate shaft.
The gearbox control drive consists of three rods connected to the forks. The forward gear forks fit into the undercuts of the synchronizer sliding sleeves, and the reverse gear fork into the undercut on the intermediate gear.
The gear selection mechanism consists of a guide plate with eight rectangular cutouts in the center, upper and lower washers, a gear lever and its housing, and a reverse locking bracket. These parts are tightened with three bolts, with which the gear selector is attached to the rear cover of the box. «Neutral» the 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. Accidental engagement of reverse gear instead of V gear is impossible due to the bent petal of the locking bracket, against which the protrusion on the lever rests. To engage reverse gear, you need to press the lever down - while its protrusion falls below the tab of the bracket.
Gearbox parts are splash lubricated. The primary and secondary shafts are sealed with oil seals, and on the secondary shaft behind the driven gear of the 5th gear there is an oil slinger. Transmission oil with a viscosity of 75W80 to 85W90 and a quality class of at least GL-4 is poured into the gearbox. Its level should be at the bottom edge of the filler hole (first make sure that the car is level).