The ability to drive is not only turning the steering wheel when maneuvering and alternating pressing the accelerator and brake pedals, it is also the right choice of the gear engagement position in the transmission shift box. Of course, CVTs and other types of automatic and semi-automatic gearboxes have been developed a long time ago, where the torque variability is selected by the node “independently, following the preset settings. They just have some limited “choice”, and they are rare on SUVs and trucks. Why, and why are they needed at all? We answer ...

How does the switch work

Different coverage or variations of its absence, changing the relief along the “up-down” vector, moving empty, with an average or full load - each of the proposed cases requires a specific speed of rotation of the propulsion wheels and the effort with which it all happens. The internal combustion engine has certain limits in terms of the numerical expression of frequency and torque, to expand it, and to be able to stably hold it in several positions, the gearbox is designed.

At the same time, automatic transmissions also have clearly defined reactions, and the work of a heavy truck is often associated with the ability to quickly, sometimes even unexpectedly vary the speed-torque of the drive shafts. Especially if you have to go on a road, the condition of which is far from ideal. And since the manual transmission is controlled remotely, by means of a lever-switch, it must also know which of its positions correspond to which moment-speed.

Of course, it would be possible to do something like a linear displacement, but in this case the rocker mechanism would resemble a thick rocker in dimensions, and it is possible that it would become cramped in the cockpit. And this is even with a standard 4-speed, 5-speed, but we won’t talk about 9, 12 and 16-speed transmissions. Therefore, designers have to “cram” all the possibilities into a complex, but compact drawing-diagram. And it is necessary to remember it because the mismatch of the selected transmission-range is not only a problem with overcoming the route, but the risk of increased wear of parts, especially if the “irregularities” are systematic.

HOW TO SWITCH

The standard version - control scheme for example, is present on the 500th MAZs. For those who are able to forget in what order everything happens, a pattern is applied on the handles of the main working tool for changing the speed-transmission. It looks like this:

1. - freely walking on the horizontal average vector handle - "neutral";
2. - left-up - first, -down - reverse;
3. - center-down - the second, -up - the third;
4. - to the right-up - the fourth, -down - the fifth.

In a checkpoint with demultiplier dividers, the pattern either remains and the upper and lower ranges overlap when the additional box is previously initiated, or the pattern itself becomes more complicated, receiving a couple of additional “branches”.

The transfer of "commands" from the handle-lever through the transverse roller is transmitted to the industrial mechanism, from there through the main thrust to the industrial lever. Then a special axial roller “turns on” and sets the gearbox shift lever itself in motion.

For such a "workhorse" as the MAZ-500 and its modifications, due to the loads experienced, problems with even the correct change in transmission speed are not uncommon. There are plenty of possible malfunctions due to which the MAZ gearbox circuit does not work as provided, but the most common are three options.

1. Do not "catch" the first and rear during the normal functioning of the rest.

To eliminate such a nuisance, you need to mark the position of the rod to its tip, loosen the coupling bolts and turn the tip clockwise by about 4-5 degrees (about 1 mm between the marks). Then the bolts are tightened and the functionality is checked. If the problem persists further, then repeat the operation, that is, move the tip a little more.

2. When the rest are working, the 4th and 5th do not work.

We do everything the same as in the previous case, but this time the tip must be turned counterclockwise.

3. The system itself works normally, but switching is hampered by the wrong position of the lever (for example, the lever rests against the panel).

We expose the neutral and disconnect the tip of the thrust from the earring of the switching mechanism. We make sure that the lever of the mechanism is also in the neutral position - the fork is located vertically, and with angular swaying, resistance to rotation is felt. If everything is so, then we wrap the locking screw on the intermediate mechanism until it stops, thereby fixing the intermediate roller "tightly". We loosen the coupling bolts and set the rod along the length so that the stopper finger easily passes through the holes of the earring and tip. We connect them and tighten the coupling bolts. After that, we unscrew the locking screw of the industrial mechanism by five turns, and lock it with a nut.

By the way, after partial disassembly of the drive, its adjustment is carried out according to the same principle.

Finally, we remind you that you can find and buy most of the components for drives, mechanisms and boxes (also transfer cases and all kinds of additional gearboxes) in the online store of our SpetsMash trading house. We work wholesale and retail, opal - cash and bank transfer, delays are expected. We organize delivery in Russia (to many cities for free), communication by phone, E-mail and through the company's website.

Switching scheme

1 236-1702060-А2 1st gear and reverse shift fork rod
2 236-1702014 Cover gasket
3 236-1702015-B2 Upper cover
4 236-1702129 1st gear and reverse fuse
5 236-1702127-A Fuse spring
6 236-1702132 Spring cup
7 236-1702087 Fork rod lock pin
8 316172-P29 Stopper
9 200-1702083 ball
10 236-1702122 Lever support gasket
11 216258-P29 Stud
12 252136-P2 Spring washer 10
12 252136-P2 Spring washer 10
13 250513-P29 Nut
14 236-1702126 Driver axle
15 236-1702125 Leash for shifting 1st gear and reverse
16 252137-P2 Spring washer
17 250615-P29 Nut
18 236-1702170-A Breather
19 262522-P2 Stopper
20 236-1702025 Set screw
20 236-1702025 Set screw
21 236-1702225-B Gear lever
22 260311-P15 Plug
23 260310-P15 Plug
23 260310-P15 Plug
23 260310-P15 Plug
24 236-1702213 Bushing
25 236-1702129 1st gear and reverse fuse
26 236-1702106 Spring
26 236-1702106 Spring
26 236-1702106 Spring
27 236-1702215 Bolt
28 236-1702209-B3 Carter
29 236-1702206-B3 Carter for remote gear change mechanism, assy
30 236-1702235 Retainer spring cup
31 252161-P2 Washer
32 236-1702100 Locking ball
33 236-1702229-A Fork rod head
34 312534-P2 Lock washer
35 310213-P29 Bolt
36 201499-P29 Bolt 10-6gх30
37 316121-P29 Plug K 1/4"
38 236-1702216 Sealing ring
39 236-1702227 Rod fork longitudinal thrust gear shift
40 236-1702024 Fork shift 1st gear and reverse
41 236-1702221 Roller
42 314040-P2 Key
43 236-1702222 Gear lever
44 236-1702241 Gasket
45 236-1702240 Crankcase cover for remote gear change mechanism
46 252135-P2 Spring washer
47 201454-P29 Bolt M8x16
48 236-1702027 Shift fork 2nd and 3rd gear
49 236-1702053 1st gear and reverse shift fork rod head
50 236-1702028 2nd and 3rd shift fork rod head
51 236-1702033 Switch fork 4th and 5th gear
52 236-1702064 2nd and 3rd shift fork rod
53 236-1702074 4th and 5th shift fork rod
Link to this page: http://www..php?typeauto=6&mark=14&model=46&group=82

The MAZ gearbox is equipped with five ranges, it aggregates with a YaMZ-236 diesel engine. It has an accelerating range and a remote control. There are also several other modifications of this node. To activate the second and third speed, the synchronizer is activated. Consider the device of this car block and its features.

Essential elements

The MAZ gearbox includes a primary shaft with a gear mounted on a crankcase with ball-type bearings. In addition, there is an intermediate shaft. From the front it looks like a device on a cylindrical roller bearing, and from the back it looks like a ball analog. The rear element compartment is protected by a cast iron cover, the first and reverse gears are cut directly on the shaft, and the rest of the ranges and power take-off are carried out through keyed drive gears.

The MAZ gearbox with a demultiplier is equipped with an intermediate shaft drive gear with a damper damper. This allows you to reduce the vibrations transformed from the power unit to the transmission box. In addition, this solution makes it possible to reduce the noise of the gear at idle. The need to install the absorber is due to the insufficient uniformity of the operation of the YaMZ-236 type motor.

The gear tooth is made separately from the hub. It is disconnected using six cylindrical springs. Residual vibrations are damped by deformation of the spring elements and friction in the damper assembly.

Device

An axle with a pair of roller bearings and a reverse gear is installed on the side between the intermediate and secondary shaft. The front gear element aggregates with the analogue of the first speed using an additional shaft, and the rear gear is engaged by activating the reverse gear.

On the MAZ semi-trailer, the front part of the secondary shaft is mounted on a roller bearing, and the rear element is installed in the ball bearing bath. On the protruding part there is a speedometer drive gear, at the back the part is protected by a cover in which the oil seal and the speedometer drive are located. On the splined rear of the shaft, a mechanism for switching first and reverse gears is installed. It should be noted that this gear is equipped with straight teeth.

Peculiarities

On the secondary shaft of the MAZ gearbox, the gear sliding structure is freely installed on steel bearings. This includes adjusting second, third and fifth speeds. The elements are protected from longitudinal displacement by means of oblique teeth and thrust rings. Three gears have constant engagement with the intermediate shaft. The gears are made with a conical base and an internal toothed surface.

The synchronizers are located between the gear elements of the second and third speeds. They provide noiseless gear shifting. The synchronizer itself consists of a clutch, which is located on the splines of the rear sleeve, as well as a body with bronze sealing rings. The skeleton aggregates with the coupling by means of ball-type retainers. The clutch is provided with toothed rims. Her fingers pass through special sockets, rings with pins and a switching fork are attached to them from the outside.

Checkpoint MAZ "Zubrenok": work

During operation of this unit, the housing ring of the housing is pressed against the cone by the gear. In this regard, friction between the contacting surfaces causes rotation and installation of the cavity on the slot with the coupling pin, while the element is blocked by the housing.

The body then engages with the gear cone due to the resulting force applied to the shifter. After the effect of friction occurs between the speed cones and the gear with the clutch, the load forces are leveled and the locking device releases the clutch from the base of the synchronizer. Next, the clutch moves by extruding the balls of the locking device, which is shifted to the side. Then the ring gear of the assembly engages with the internal teeth of the mechanism, which entails the inclusion of one or another gear.

Functioning scheme

There are three adjusting rods in the crankcase cover tidal sockets. Their forks are aggregated with the first and reverse gear control carriage, as well as with a pair of clutch synchronizers. Switches are equipped with ball locks and locks.

The diagram of the MAZ gearbox, presented below, confirms that the most loaded bearings receive lubrication under the resulting operating pressure. The oil comes from the bath through a detachable filter element. It is equipped with a magnet that allows liquid to enter by suction of the gear pump. This unit is driven by the front edge of the intermediate shaft. Next, the mixture is pumped through a groove in the crankcase, enters through the channel of the primary and secondary shafts into the gear bearings of the mechanism. The remaining elements are lubricated by spraying the incoming oil.

Oil pump

The MAZ-4370 gearbox is equipped with an oil pump, which has a ball valve that serves to limit the oil pressure in the gearbox system. The assembly crankcase is equipped with an internal baffle, which causes the waste oil to be released through two holes blocked by special plugs.

Gear control is carried out by means of a lever located in the cab. The principle of operation of the circuit is a remote drive located above the power unit. In the bracket of the cover of the crankcase of the transmitting unit, a pair of support rollers is provided, which serve to switch speeds using grooves and necks placed on the adjusting rods.

In the middle position, the lever is located with a pin with a lock and a spring up. At this time, the lower analogue of the fuse is activated along with the spring. The pin is externally mounted in the oscillating compartment of the first and reverse gears. The leash is mounted on a pivot pin mounted in front of the box lid.

Other details

The MAZ semi-trailer in the system is equipped with a front roller that controls the second lever inserted into the head of the movable rod of the bracket. The outer part of the movable rod is connected to the intermediate control mechanism using a cardan elongated rod. The fixing bracket is attached to the vehicle frame.

The lower edge of the shift lever is connected to the same node. Mounting method - similar to the above method. Part of the arm goes through the cabin floor, ensuring the integrity of all other connections. This design makes it possible to tilt the cab without the need for separation and deformation of existing elements and assemblies.

In conclusion

I would like to dwell in more detail on the features of the gearbox of the MA3-2G0 machine. This block is almost identical to the device on the Drive gear does not have a damper, but the second, third and fifth speeds are switched on using the secondary shaft on needle-type bearings. The switching lever is located on a ball bearing, the body of which is fixed on the cover of the switching box. It has a reverse activation fuse, as well as a pin with a spring installed in the steering bracket socket. The node in question proved to be excellent as a direct competitor of domestic and foreign analogues, in accordance with the combination of price and quality parameters.

In this article, we will tell you what functions the gearbox performs in the MAZ engine, make several recommendations for repair, and also indicate the MAZ gearshift scheme with a divider, which you can examine and study in detail.

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Appointment of the checkpoint

In the gearbox there is such an element as a gear, usually there are several of them, they are connected to the gear control lever and it is due to them that gear changes occur. Gear changes control the speed of the car.

That is, in other words, gears are gears. They have different sizes and different rotation speeds. In the process of work, one clings to the other. The system of such work is due to the fact that a large gear clings to a smaller one, the rotation increases, and at the same time the speed of the MAZ car. In cases where a small gear clings to a large one, the speed, on the contrary, drops. The box consists of 4 speeds plus reverse. The first is considered the lowest and with the addition of each gear, the car starts to move faster.

The box is located in the MAZ car between the crankshaft and the driveshaft. The first one comes directly from the engine. The second is directly connected to the wheels and drives their work. The list of works that lead to speed adjustment:

1. The motor sets the movement of the drive and crankshaft.
2. Gearbox gears receive a signal and set in motion.
3. Using the gear lever, the driver selects the desired speed.
4. The speed selected by the driver is transmitted to the cardan shaft, which drives the wheels.
5. The vehicle continues to move at the selected speed.

Device diagram

The scheme of the gearshift device for a gearbox with a divider on a MAZ is not simple, but it will help you a lot when making repairs. The step gearbox on the MAZ consists of such elements as the crankcase, shafts, mortar, synchronizers, gears and other equally important elements.

9 speed

Such a unit is installed, in most cases, on trucks or cars that will be subjected to high traffic.

8 speed

This unit, like its predecessor, is popular among machines with high payloads.

5 speed

The most popular among cars.

Want to keep your divider box in good condition for years to come? Then she needs care and elementary checks. It is necessary to monitor the work of such elements as gears, a mortar, the control lever itself, and so on. Has it happened that the breakdown is unavoidable? We will give you the following recommendations for self-repair:

• familiarize yourself with the diagram and instructions for your mechanism in detail;
• in order to carry out repairs, first of all it is necessary to remove the box completely and only after that you can proceed with the repair;
• after you pull it out, do not rush to disassemble it completely, sometimes the problem is on the surface, pay special attention to all the details, if you see suspicious "behavior", then most likely the problem is in this element;
• if you still have to disassemble the box completely, put all the parts in the order of disassembly, so as not to get confused at the moment when you collect it back.

If you are not confident in your abilities, do not have certain skills and knowledge, contact the service center. Is there no such possibility? Well, it's never too late to learn new and useful things. Ask questions in the comments, we will give you open and detailed answers.

In this article, a gearshift scheme for MAZs of all types was considered. We hope that the information was useful to you in the repair. Let your box serve you for many years!

Video "Checkpoint operation"

You can see the principle of operation of a mechanical box in this video.

The gearbox drive of Maz-5516, Maz-5440, 64229, Maz-54323, 54329 and YaMZ-239 cars is shown in Figure 4.

During operation, if necessary, the following adjustments of the gearbox drive are made:

The procedure for adjusting the control of the YaMZ-239 gearbox for Maz-5516, Maz-5440, 64229, Maz-54323, 54329 cars is as follows:

Set lever 2 to neutral position;

By longitudinal movement of the plate 16 with the bolts 17 released, set the angle a of the lever 1;

By changing the length of the rod 3 set the angle.

In case of insufficient plate travel 16 or thrust adjustment range 3, loosen bolts 5, shift or rotate the thrust 6 relative to shank 4, tighten bolts 5 and repeat the adjustment of angles a, b, as indicated above.

Angle a should be 80°, angle b - 90°.

Adjust the locking device of the telescopic elements of the YaMZ-239 gearbox for Maz-5516, Maz-5440, 64229, Maz-54323, 54329 vehicles with the cab raised as follows:

Unpin the pin 8 and disconnect the rod 6 from the fork 9 of the gear lever;

Push the inner rod 6 until the stop of the protrusions of the earring 12 into the grooves of the tip 15;

While holding the mechanism in a compressed state, screw the shank until the mechanism is blocked by the sleeve K) under the influence of spring 11:

Tighten locknut 13, check the operation of the locking mechanism. When the mechanism is locked, axial and angular play should be minimal.

In the unlocked position, the sleeve 10 is shifted to the left. The movement of the extension must be smooth, without jamming, and the locking mechanism must provide a clear fixation of the rod extension in its original position.

When connecting the link 6 to the fork 9, the hole in the earring for the pin 8 must be located above the longitudinal axis of the link 6. Adjust the drive with the engine off.

When lifting the cabin, oil under pressure from the cabin lifting pump is supplied through the hose 7 to the cylinder of the blocking device and the mechanism 6 is unlocked.

After lowering the cab, in order to securely fix the telescopic mechanism 6 in the locked position, it is necessary to move the gearshift lever 1 forward in the direction of the vehicle in a motion similar to shifting gear. In this case, the mechanism is blocked and is then ready for operation.

The gearshift diagram of the gearbox of the Maz-5516, Maz-5440, 64229, Maz-54323, 54329 and YaMZ-239 cars, see Figure 5.

Fig.4. YaMZ gearbox control drive for Maz-5516, 64229, Maz-54323, 54329

1 - lever; 2 - lever; 3,4 - thrust; 5.17 - bolt; 6 - thrust (telescopic mechanism); 7 - hose; 8 - finger; 9 - fork; 10 - bushing; 11 - spring; 12 - earring; 13 - locknut; 14 - shank; 15 - tip; 16 - plate; 18 - switch

Gearbox control drive for Maz-5516, Maz-5440, 64229, Maz-54323, 54329 vehicles with MAN engine.

When operating the gearbox of Maz-5516, Maz-5440, 64229, Maz-54323, 54329 vehicles, be guided by the following:

The control of the main gearbox and the demultiplier is carried out using the gearbox lever according to the diagram shown in Figure 19 (ZF gearbox).

The transition of the slow range of the demultiplier to the fast one is carried out by moving the lever in the neutral position away from you, overcoming the clamp force, from the fast range to the slow one - in reverse order.

The divider is controlled by a flag on the gear lever handle. The transition from the slow range (L) to the fast range (S) and vice versa is carried out by pressing the clutch pedal all the way after the flag is moved to the appropriate position. Switching is possible without disengaging the gear in the main gearbox.

Adjustment of the gearbox control drive of the gearbox of cars Maz-5516, Maz-5440, 64229, Maz-54323, 54329

During operation, if necessary, the following adjustments are made to the gearbox drive of Maz-5516, Maz-5440, 64229, Maz-54323, 54329 cars for MAN engines:

Adjustment of position of the lever in the longitudinal direction;

Adjustment of the position of the lever in the transverse direction;

Adjustment of the locking device of the telescopic drive elements.

The position of the lever 1 (Figure 7) in the longitudinal and transverse directions is adjusted by moving and rotating the rod 5 in the shank 6 with the bolts 7 released.

In this case, the angle a must be 85°, the angle e=90°. The angle a can also be adjusted by moving the plate 3 with the bolts 2 released.

Fig.5. Gearshift diagram of the gearbox of cars Maz-5516, Maz-5440, 64229, Maz-54323, 54329, YaMZ-239

M - slow range; B - fast range.

Fig.6. Gearshift diagram of the ZF gearbox for Maz-5516, Maz-5440, 64229, Maz-54323, 54329

L - slow range; S - fast range.

Fig.7. Gearbox control drive for Maz-5516, Maz-64229, Maz-54323, 54329

1 - lever; 2, 7 - bolt; 3 - plate; 4 - hose; 5 - intermediate mechanism; 6 - shank; 8 - growl

The gearbox drive of Maz-5440 cars is shown in Figure 8.

Switching of the main box is made by lever 1 of the remote control mechanism. The additional box is controlled by the range switch 18, located on the gear lever 1.

When the range switch is in the lower position, the fast range in the additional box is turned on, with the upper position, the slow range is switched on.

During operation, if necessary, the following adjustments are made to the gearbox of Maz-5440 cars:

Adjusting the angle of inclination of the lever 1 in the longitudinal direction;

Adjusting the angle of inclination of the lever 1 in the transverse direction;

Adjustment of the blocking device of the telescopic mechanism. To adjust the angle of inclination of the lever in the longitudinal direction, you should:

Set lever 2 to the neutral position by tightening the neutral position lock on the shift mechanism 20 (for the YaMZ gearbox - 238M).

Check the neutral position of the gearbox of the gearbox of Maz-5440 cars by moving the lever shaft 2 in the axial direction by pressing it with your hand. In this case, the roller should move by 30 - 35 mm;

Loosen the tightening of the bolts 17 and by moving the plate 16 longitudinally, set the angle "a" to 90 degrees;

If the plate 16 travel is insufficient, release the bolts 5, move the rod 6 relative to the shank 4, tighten the bolts 5 and repeat the adjustment of the angle "a" by moving the plate 16.

The adjustment of the lever 1 in the transverse direction is carried out by changing the length of the transverse link 3 by disconnecting one of the tips with unscrewing the nut of its fastening, followed by adjusting the length so that the lever 1 takes a vertical position.

After adjustment, return the neutral position lock to its original position (for the YaMZ-238M gearbox).

The adjustment of the locking device of the telescopic mechanism of the gearbox of Maz-5440 cars should be done as follows:

Unpin the pin, unscrew the nut, remove the pin and disconnect the rod 6 from the fork 9 of the gear lever;

Loosen the locknut 13 and unscrew the shank 14 until the thread stops;

Push the inner rod 6 until the stop of the protrusions of the earring into the grooves of the tip 15;

While holding the mechanism in a compressed state, screw in the shank 14 until the mechanism is blocked by the sleeve 10 under the influence of the spring 11;

Tighten locknut 13, check the operation of the locking mechanism. When the mechanism is locked, axial and angular play should be minimal. In the unlocked position (sleeve 10 shifted to the right), the inner link must be pushed out by a return spring by 35 - 50 mm.

Further movement of the extension must be smooth, without jamming, and the locking mechanism must ensure a clear fixation of the extension rod in its original position.

Do not allow bending and curvature of the drive rod and its telescopic components. Adjust the gearbox drive with the engine off.

Fig.8. Gearbox control drive for Maz-5440 cars

1,2 - lever; 3, 4, 6 - thrust; 5, 7, 17 - bolt; 8 - finger; 10 - bushing; 11 - spring; 12 - earring; 13 - nut; 14 - shank; 15 - tip; 16 - plate; 18 - switch 19 - ball; 20 - switching mechanisms.

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3.2. Gearbox and its drive. Device.

On MAZ vehicles, an eight-speed dual-range gearbox YaMZ-238A is installed with synchronizers in all gears, except reverse. The gearbox consists of a main two-stage gearbox and a two-stage additional gearbox (downshift).
The gearbox device is shown in Fig.44. Installation of all parts of the gearbox is carried out in the crankcases of the main and additional boxes, which are interconnected, and then assembled to the clutch housing; a single power unit is formed as part of the engine, clutch and gearbox.
The primary shaft 1 of the main box is mounted on two ball bearings; driven clutch discs are installed on the front splined end, and the rear end is made in the form of a ring gear of the constant mesh gear of the main box.
The output shaft 5 of the main box in front rests on a cylindrical roller bearing mounted in the bore of the gear rim of the drive shaft, and at the rear - on a ball bearing mounted in the front wall of the crankcase of the additional box. The rear end of the secondary shaft is made in the form of a ring gear, which is a gear of constant engagement of the additional box.
The gears of the second and fourth gears of the output shaft of the main box are mounted on plain bearings made in the form of steel bushings with a special coating and impregnation, and the gears of the first gear and reverse gear are mounted on roller bearings.
The intermediate shaft 26 of the main box in front rests on a roller bearing mounted in the front wall of the main box crankcase, and at the back - on a double-row spherical bearing placed in a cup installed in the rear wall of the main box crankcase. In the tides of the crankcase of the main box, an additional axle is installed for the reverse intermediate gear. The reverse gear is switched on by moving the reverse carriage 24 forward until it is connected to the ring gear of the reverse gear 25, which is in constant engagement with the reverse intermediate gear.
The secondary shaft 15 of the additional box in front rests on a cylindrical roller bearing located in the bore of the gear rim of the secondary shaft of the main box, at the back - on two bearings: a cylindrical roller bearing and a ball bearing, installed respectively in the rear wall of the crankcase of the additional box and the bearing cover of the secondary shaft.
On the splines of the middle part of the secondary shaft of the additional box, gear shift synchronizers are installed, and on the rear splined end there is a flange for fastening the cardan shaft. On the middle cylindrical part of the shaft, on roller cylindrical bearings, gear 11 of the additional box is installed.
The intermediate shaft 19 of the additional box in front rests on a cylindrical roller bearing installed in the front wall of the additional box crankcase, and at the rear - on a double-row spherical bearing placed in a glass mounted in the rear wall of the additional box crankcase. Downshift gear 22 is installed on the front splined end of the intermediate shaft of the additional box. At the rear of the intermediate shaft, a ring gear is made, coupled with the downshift gear of the secondary shaft of the additional box.
To switch gears in the main box, inertial synchronizers with conical friction rings are used, and in the additional box - with friction discs.
Gear shifting in the main box is carried out using a mechanical remote drive, and the additional box is controlled using a pneumatic drive.

Remote drive of the main box (Fig. 45).

Telescopic type, consists of a mechanism located directly on the gearbox 13, and a system of rods and levers connected to the 3 gear lever mounted in the cab.
In the tides of the top cover 1 (Fig. 46) of the main box, three rods are mounted: on the extreme right (along the direction of the car) the fork 3 of the reverse gear is fixed, on the middle - the fork 4 of the first and second gears of the main box, and on the third - the fork 8 shifting third to fourth gear of the main box.
Rods 5, 20 and 21 move in the guide supports of the top cover with the help of lever 22. There are heads (11 and 17, respectively) on the reverse gear and the shift rod of the first and second gears of the main gearbox. The lever 22 enters the head 17 directly, and the head 11 through the leash 15 of the reverse gear.
To enable the third and fourth gears of the main gearbox, the lever 22 can enter directly into the groove of the fork 8 for shifting these gears. The position of the reverse rod is fixed in the cover with the help of a fuse 16, which is included in the leash 15 under the action of a spring 12 placed in a special glass 13. Only by overcoming the force of the spring of this fuse, you can turn on the reverse. The rods with the gear engaged and in the neutral position are held by ball clamps. To prevent the possibility of simultaneous engagement of two gears, a special ball-type lock is installed in the rods.
On the top cover of the main box, there is a crankcase 11 (see Fig. 45) of the remote control mechanism of the main box, in which the gear shift shaft 12 is located with the lever 14 fixed on it and the intermediate lever 18 connected with the longitudinal rod 7 of the remote drive.
In the crankcase of the remote mechanism there is a ball lock 9 for gear selection. Longitudinal thrust 7 can perform both longitudinal and angular movement. The angular movement of the rod causes axial movement of the shaft 12, which leads to the connection of the lever 14 sitting on it with a certain slider in the top cover of the main box 13. The movement of the longitudinal rod causes the rotation of the gear shift shaft 12 and the lever 14 sitting on it. moves along with the fork until the appropriate gear is engaged.
The additional box is controlled by means of a pneumatic valve by the switch 1 (see Fig. 45) of the ranges located on the handle of the gear lever 3.

The switching mechanism of the additional box (Fig. 47).

It consists of a pressure reducing valve 12, an air distributor 6, a pneumatic cock 5, an inlet valve 8, a working cylinder 1 and air ducts.
Reducing valve 3 (Fig. 48) serves to reduce the pressure of compressed air supplied from the pneumatic system of the car to 4.75 kgf / cm² - the working pressure of the pneumatic system of the gearbox. The air distributor 23 directs compressed air from the inlet valve 17 into one or another cavity of the working cylinder 25 and bleeds air from its cavities.
Pneumocrane 5 controls the air distributor. With the 6 range switch down, the air distributor spool is set to the position corresponding to the direct transmission in the additional box. With the switch up, to the downshift position.
The inlet valve 17 supplies compressed air through the air distributor 23 to the working cylinder 25 only when the gear in the main box is switched off. When the gear is on in the main box, the valve inlet is closed by the pusher 16 and air does not enter the air distributor and the working cylinder, the unloading hole in the valve body is open, both cavities of the working cylinder are connected to the atmosphere.
When the range switch 1 is raised (see Fig. 45), the cable 6 moves the spool 3 (Fig. 49) to a position in which compressed air supplied from the pressure reducing valve to channel A through the pneumatic valve channel enters channel B and then to the air distributor on downshifting. Channel B at this time is connected to the atmosphere through filter 8.

When the range switch is lowered, the cable moves the spool 3 to a position where compressed air enters channel B through channel A and from there to the air distributor for direct transmission. At this time, channel B is connected to the atmosphere through cover 5.
The gearshift mechanism of the additional box is located in the top cover of its crankcase. Here is the rod 13 (see Fig. 44), connected with the piston of the pneumatic cylinder 14. The direction of movement of the rod with the fork 10 of the gear change of the additional box fixed on it depends on the pressure supplied to the pneumatic cylinder to the left or right of the piston, which causes the large 20 or small 21 synchronizer, i.e., reduction or direct transmission of an additional box.
On the top cover of the additional box there is a synchronizer sensor, downshift engagement. When the rod 13 and the fork 10 of the gear shift of the additional box are moved from one position to another, the control lamp connected to the switch terminal 35 lights up in the driver's cab. The lamp goes out as soon as the selected (direct or downshift) gear is fully engaged.
In addition, there is a locking device on the top cover of the additional box to turn off the additional box when the vehicle is towed. To do this, having set the fork 10 in the neutral position, the locking bolt 9 is screwed all the way into the hole made on the rod, and it is locked in this position with a nut.

Gearbox lubrication system.

It is combined: the gear bearings of the secondary shafts of the main and additional boxes are lubricated under pressure, the gear teeth and shaft bearings are spray lubricated. The oil is sucked in from the oil bath of the crankcase through the intake 29 and the system of channels by a gear oil pump. The pump drive is carried out from the end of the intermediate shaft of the main box. The pump has a pressure reducing valve, which is adjusted to a pressure of 0.78 kgf / cm² and, in case of an excessive increase in oil pressure, connects the pump discharge channel to the suction channel. The oil baths of both crankcases are interconnected by a channel to ensure the same oil level in them. The internal cavity of the gearbox housings communicates with the atmosphere with the help of a breather.
The gearbox has an oil filler hole on the cover of the main box, an oil level control hole on the side wall of the main box, and two drain holes each from the bottom of the crankcases of the main and additional boxes.