The gearboxes differ in the speedometer drives, each of which corresponds to its own final drive ratio. For external differentiation, a paint mark is applied to the speedometer drive: blue for final drive ratio 3.9; red for 4.1, not painted for 4.3. Also on the clutch housing (opposite the breather) the marking is applied with paint, the number 5.
The models described are equipped with a four-speed gearbox with synchronizers on all forward gears. Some cars are equipped with a five-speed gearbox, made on the basis of a four-speed gearbox.
The gearbox consists of a housing 46 (Fig. 115), in which the primary, intermediate and secondary shafts with gears and synchronizers are located, and a mechanical gear shift drive.
Fig. 115. Gearbox:
1 - primary shaft seal; 2 - rear bearing of the primary shaft; 3 - clutch housing; 4 - bearing mounting ring; 5 - secondary shaft needle bearing; 6 - Thrust washer of the IV gear synchronizer spring; 7 - toothed ring of the 4th gear synchronizer; 8 - breather; 9 - synchronizer clutch III and GU gears; 10 - synchronizer clutch hub; 11 - synchronizer locking ring retaining ring; 12 - synchronizer locking ring; 13 - synchronizer spring; 14 - driven gear of the 3rd gear; 15 - driven gear of the 2nd gear; 16 - secondary shaft; 17 - driven gear of 1st gear; 18 - 1st gear bushing; 19 - secondary shaft intermediate bearing; 20 - locking plate; 21 - reverse driven gear; 22 - lever rod; 23 - thrust cushion; 24 - elastic pillow; 25 - spacer sleeve; 26 - locking sleeve; 27 - speedometer drive pinion; 28 - secondary shaft seal; 29 - elastic coupling flange: 30 - nut; 31 - centering ring seal; 32 - retaining ring; 33 - centering ring; 34 - secondary shaft rear bearing; 35 - mud deflector; 36 - driven gear of the speedometer drive; 37 - rear cover of the gearbox; 38 - speedometer drive; 39 - Reverse gear fork; 40 - Reverse drive pinion; 41 - reverse intermediate gear; 42 - intermediate gear axis; 43 - intermediate shaft rear bearing; 44 - 1st gear drive pinion; 45 - synchronizer clutch of 1st and 2nd gears; 46 - gearbox housing; 47 - 2nd gear drive pinion; 48 - leading gear of the 3rd gear; 49 - filler and inspection hole plug; 50 - gearbox lower cover; 51 - intermediate shaft; 52 - intermediate shaft constant mesh gear; 53 - front bearing of intermediate shaft; 54 - bearing clamp washer; 55 - bolt; 56 - constant mesh gear of the primary shaft; 57 - spring washer; 58 - retaining ring; 59 - Front gearbox cover; 60 - primary shaft.
The primary shaft 60 rotates in two bearings: the front one is located at the end of the crankshaft, the rear one is in the socket of the gearbox housing. The shaft has two toothed rims. The constant engagement gear of the primary shaft 56 with helical teeth is in constant engagement with the gear 52 of the intermediate shaft, and the rim 7 with straight teeth is the rim of the synchronizer of the fourth gear. The intermediate shaft 51 is a block of four gears installed in two bearings 43 and 53. The secondary shaft 16 is installed on three bearings. Two synchronizers are located on it. Each of them consists of a sliding clutch 9 and 45, a hub 10, blocking rings 12 and springs 13. The hub, rigidly connected to the secondary shaft, has external rims on which the sliding clutch 9 is located. The blocking rings are connected with their internal rims to the rims of the synchronizers of the primary shaft and gear 14 of the third gear. The rings are pressed to the conical surfaces of the clutch by springs 13. The intermediate gear 41 of the reverse gear is freely located on the axis 42.
The gears are switched using a mechanical drive consisting of three rods on which forks are fixed, which enter the groove of the sliding clutches 9 and 45 of the synchronizers, and fork 39, which enters the groove of the reverse gear 41.
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