DIY yamz 239 gearbox repair

Technical characteristics of the YaMZ-239 gearbox

The basic model of the gearbox of the YaMZ-239 gearbox is used in conjunction with the YaMZ-7511 engines on MAZ vehicles, and on its basis they are developed with maximum unification and additional modifications and configurations are made for vehicles of other enterprises.

The basic model of the YaMZ-239 gearbox is designed to work with engines of the YaMZ-7511 type on MAZ vehicles, equipped with a gearshift mechanism for remote control, manufactured by the Minsk Automobile Plant; an intermediate shaft with a toothed ring at the rear end of the shaft for power take-off of not more than 73.5 kW (100 hp) and a place on the end of the range crankcase for installing a power take-off.

The YaMZ-239 gearbox is equipped with a speedometer drive in the form of a worm gear from the output shaft and a bearing cap of the output shaft, which ensures the installation of replaceable gears at an automobile plant, depending on the speed characteristics of various models and modifications of cars; sensor and solenoid valve of the electronic blocking system for turning on the lower range of the range.

The YaMZ-239 gearbox is equipped with a remote gearshift drive mechanism and a flange for connecting the car's propeller shaft.

Since 2006, engines of the YaMZ-7511 type for cars of the Minsk Automobile Plant have been equipped with YaMZ-239-02 gearboxes, in which, compared to the base model, the mechanical speedometer drive is excluded, and the gearbox is made for the use of an electronic speedometer.

The gearbox of the YaMZ-2391 modification and its configuration differs from the base one in the modified gear ratio of the 5th and, accordingly, the 9th gear, due to the use of the gear of the 5th gear on the intermediate shaft with a large number of teeth (45 instead of 43) and gears 5 -th gear on the secondary shaft with fewer teeth (23 instead of 25).

The YaMZ-239 gearbox (Fig. 1) with YaMZ-7511 engines on MAZ vehicles is mechanical, eight-speed, with synchronizers in all gears, except for reverse, consists of a main four-speed gearbox and a dual-band planetary demultiplier.

The mechanism for switching the ranges of the demultiplier of the YaMZ-239 gearbox is equipped with an automatic system for blocking the inclusion of the lower range (ASBP).

The ASBP relay is designed in such a way that it allows switching on the lower range at a speed of the output shaft of the YaMZ-239 gearbox of no more than 920 min-1, which, depending on the gear ratios of the drive axle, the transfer case, the rolling radius of the wheels, corresponds to a vehicle speed of 25 - 30 km / h.

For each specific car, this value can be determined with sufficient accuracy as the quotient of the division of the maximum (kinematic) speed.

The filling capacity of the YaMZ-239 gearbox lubrication system is 7.5 liters. The oil level is determined by the lower edge of the inspection hole on the right side of the spacer located between the crankcase of the main gearbox and the range multiplier.

The oil filler plug is located on the top cover of the main box on the left side. The inspection hole can also be used as a filling hole.

Fig. 1. Gearbox of the YaMZ-239 check point

1 - clutch housing; 2 - adjusting gaskets of the input shaft; 3 - crankcase breather; 4 - secondary shaft; 5 - breather of the air distributor; 6- air distributor; 7 - centering ring; 8 - lower range engagement clutch; 9 - adjustment bolt of the shift rod stopdemultiplier with lock nut; 10 - switch of the signaling device for switching the demultiplier; 11 - secondary shaft adjusting gaskets; 12 - satellites; 13 - fork for switching the demultiplier; 14 - cylinder for switching the range multiplier; 15 - high range engagement clutch; 16 - speed sensor of the low range blocking system; 17 - adjusting spacers of the output shaft; 18 - mounting bolt in the output shaft flange, 19 - output shaft; 20 - sun gear thrust ring; 21 - demultiplier housing; 22 - ring gear; 23 - sun gear; 24 - spacer; 25 - pump intake cover with mesh; 26 - drain plug with a magnet; 27 - power take-off gear; 28 - main box crankcase; 29 - intermediate shaft; 30 - oil pump; 31 - primary shaft.

Before installing the YMZ-239 gearbox demultiplier with a spacer on the main box crankcase and a spacer on the demultiplier crankcase, apply an anaerobic sealing compound on the gaskets on both sides with a continuous strip 2-3 mm wide along the contour.

When installing the bearing cap of the input shaft, the demultiplier with a spacer on the crankcase of the main box, the cover of the rear bearing of the output shaft of the demultiplier, ensure the minimum axial backlash of the shafts using shims selected as follows:

Measure the size of the depth of the groove for the bearing in the bearing cover of the input shaft of the YaMZ-239 gearbox, taking into account the thickness of the gasket with an accuracy of 0.1 mm.

Measure the size from the end of the outer ring of the bearing to the surface of the crankcase wall of the YaMZ-239 gearbox with the bearing pressed against the stop with an accuracy of 0.1 mm.

Measure the size from the end of the outer ring of the bearing to the surface of the crankcase with an accuracy of 0.1 mm, making sure that the centering ring is pressed in until it stops, and the snap ring and bearing are firmly pressed against the center ring.

Measure the depth of the bearing bore in the gear coupling, taking into account the spacer and the bore, with an accuracy of 0.1 mm.

Measure the size from the end of the outer ring of the bearing to the surface of the crankcase of the YaMZ-239 gearbox with an accuracy of 0.05 mm, making sure that the snap ring and bearing are firmly pressed against the crankcase surface.

Measure the size from the gasket to the thrust ring in the cover recess with an accuracy of 0.05 mm.

When repairing the YMZ-239 gearbox demultiplier with the replacement of synchronizer parts, adjust the required stroke length when the high range is turned on, ensuring the unloading of the fork cracks when operating at the higher range, for which:

Turn on the high range in the YaMZ-239 gearbox range, supplying air under pressure from 784 to 833 kPa (8.8.5 kgf / cm2) to the rear cavity of the pneumatic cylinder, make sure that the high range engagement clutches are fully engaged.

When fully engaged, the indicator lamp should go out, the propeller shaft mounting flange should not rotate by hand.

Screw the adjusting bolt all the way into the piston rod (when the bolt rotates, an increase in resistance to rotation should be felt). Repeat the operation several times, making sure that the stop is felt at the same position of the bolt head.

Turn the adjusting bolt from the position of its stop to the end one turn (5 edges of the head) and while holding it in this position, lock it with a lock nut, tightening it with a torque of 137-157 Nm (14-16 kgf / cm).

After adjustment, the propeller shaft mounting flange should turn easily without jamming, by hand. Turn the flange through an angle of at least 360 degrees.

Maximum input torque KPP-239, Nm - 930

Weight with clutch housing, kg - 240

Gear ratios of the YaMZ-239 gearbox: 1st gear - 5.22, 2nd gear - 2.90, 3rd gear - 1.52, 4th gear - 1.00, 5th gear - 0.664, Reverse - 5.22

Gear shift mechanism of the YaMZ-239 checkpoint

The design of the gearshift mechanism of the YaMZ-239 gearbox is shown in Figure 12, and the top and bottom view of the gearshift mechanism is shown in Figures 13 and 14, respectively.

The gearshift mechanism of the main gearbox is built into its upper cover 1 (see Figure 12) and has three rods - a rod for 4-5 gears 26, 2-3 gears 30, 1st gear and reverse gear 29.

The 4-5th gear fork is attached to the rod of 4-5 gears.On the other two rods, respectively, the movement head and the shift fork of the 2nd and 3rd gears and the movement head and the shift fork of the 1st gear and reverse gear are fixed.

Heads and forks on the rods are attached and fixed (installed) on the rods using special set screws for each head and forks.

Each set screw, after tightening, is countered with a 1.2 mm diameter cotter wire, 100 mm long.

Each gear shift rod is fixed relative to the top cover in three positions: neutral (gears are not included, respectively) and two others (when each of the two gears is engaged).

Each stem retainer has a standard 11mm ball and compression spring fitted into the holes in the bonnet, with the ball sequentially sliding into the grooves on the stem after it has been moved from neutral to engaged.

Figure 2 - Gear shifting mechanism with gear shifting control mechanism and air distributor of the YaMZ-239 gearbox

The rod of the first gear and reverse can be moved only after the safety device is removed from the hole in the rod head by applying force to compress the spring.

This action is carried out by a lever mounted on the flange of the top cover or a lever device for remote control of the transmission.

To prevent the possibility of simultaneous engagement of two gears, a locking device is provided in the mechanism, which does not allow simultaneously engaging two gears.

The locking device consists of a pin 36 installed in the shaft hole of 2-3 gears and four balls 35 with a diameter of 9.525 mm, which are installed in the cover holes by two between the middle and outer rods.

When the middle rod moves to the right or left, the locking balls come out of its grooves and enter the grooves of the outer rods, thereby locking them in a neutral position.

If one of the outer rods moves, then two locking balls are displaced from the groove of this rod and enter the groove of the middle rod.

At the same time, the balls press on the movable pin located in the middle rod, moving it.

The pin acts on the balls located between the middle stem and the stem, which is in the neutral position, as a result of which the ball closest to the outermost stem enters its groove.

Thus, the middle and one of the outer rods are locked in the neutral position.

DISASSEMBLY AND ASSEMBLY OF KP TYPE YAMZ-239

Depending on the upcoming volume of repairs, there are two options for disassembling the gearbox: partial or complete.

Partial disassembly is carried out for routine repair, the amount of disassembly of the gearbox is determined depending on the malfunction to be rectified.

Complete disassembly is carried out for overhaul of the gearbox and for gearboxes, after long mileage of the vehicles on which they were operated.

It is recommended to disassemble the gearbox on a special stand (see Figure 33) or, in exceptional cases, on a wooden stand (see Figure 34) using a hoist. The use of the hoist must be in accordance with the "Rules for the Construction and Safe Operation of Hoists" PB10-382-00, approved by Rostekhnadzor.

When disassembling using a special stand, the following sequence of works is recommended:

- install the gearbox on the stand, fixing it with three bolts using the M 12 threaded holes on the right side platform of the gearbox housing;

- disconnect the hose 55 (see Figure 2) of the release clutch lubricant with a clip with a spring of the return clutch 54 from the clutch housing by unscrewing the fastening nut 57 with an open-end wrench S = 24;

- remove the clutch 10 from the primary shaft cover by moving the clutch along the cylindrical surface of the cover in the direction opposite to the side of the front end of the gearbox housing;

- loosen the two bolts of the clutch release fork using the S = 14 wrench;

- by blows of a soft metal hammer on the end face of the clutch release shaft 8 from the side of the splined part, knock out the plug 59 from the groove in the clutch housing and remove the circlip 60;

- using a hammer and a punch (round roller 24.5 mm in diameter, 300 mm long), move the clutch release shaft until it comes out of the fork 9 and then out of the clutch housing 5. In this case, one bushing 61, one retaining ring should remain on the removed shaft 60 and shaft seal parts 62, 63 and 64;

- remove the oil supply pipe 65 from the oil pump to the primary shaft cover by unscrewing two bolts 52 with a key S = 19 and remove 4 sealing washers 53;

- remove the clutch housing 5 by unscrewing eight bolts 50 using an S = 22 socket wrench and remove eight flat washers 51;

Figure 33 - Stand for assembly and disassembly of the gearbox KP YaMZ-239
1 - gearbox mounting plate; 2 - stand assembly (two channels # 18, connected by electric arc welding);
3 - swing mechanism (worm gear or other, determined by the manufacturer of the stand);
4 - support plate (sheet 16x600x720, steel with a carbon content of no more than 0.2%); 5 - frame (four channels connected by welding)

Figure 34 - Plate assembly for fastening the KP YaMZ-239
1 - base; 2 - left bracket assembly; 3 - left base amplifier; 4 - boss; 5 - bolt М16х45; 6 - right base reinforcement (steel corner 40x25); 7 - right bracket

Figure 35 - Wooden stand for assembling and disassembling the gearbox of the KP YaMZ-239 1 - Gearbox assembly, 2 - Stand made of pilings

- disconnect three air ducts from the air distributor by unscrewing three special bolts with a wrench with S = 14 and remove six sealing washers;

- remove the gear change mechanism by unscrewing the twelve bolts securing the top cover with an S = 17 socket wrench and remove the spring washers. The gearshift mechanism can be disconnected from the gearbox housing only after the upper cover is vertically movable relative to the two locating pins of the gearbox housing. To ensure mobility, light blows are made on the top and sides of the cover flange, and a wedge puller should be inserted (hammered in) between the mating surfaces of the crankcase and the upper cover (see Figure 36). It is recommended to move the upper cover (gearshift mechanism housing) with the initial preservation of approximate parallelism of the mating surfaces of the crankcase and the cover, which will provide less distortions in the pin joints of the upper cover with the gearbox crankcase.

- remove the demultiplier (disconnect from the main gearbox), for which the gearbox is turned on the stand using a rotary device (or tilted on a wooden stand using a lift) to the vertical position of the shafts, so that the demultiplier takes the upper position. To ensure the possibility of using the lift to the flange of the demultiplier shaft, fasten the eye-bracket with two M14 bolts with nuts. The scheme for removing the range multiplier with a sketch of the eyelet is shown in Figure 37. Unscrew the eight bolts 30 (see Figure 2) with the S = 22 mm wrench (see Figure 2) fastening the range multiplier to the main gearbox housing, taking into account that two bolts are screwed into the threaded holes of the range spacer. The named bolts can be loosened with an S = 22 socket and open-end wrench. If the demultiplier is difficult to detach, it is recommended to use a special demultiplier puller (the design is shown in Figure 38), installed in place of the top cover, and a puller bolt 3 with a stop 2 in the gearbox housing in accordance with the diagram in Figure 37.

- turn the gearbox to ensure the horizontal position of the shafts;

- remove the bearing cover 11 of the input shaft by unscrewing the six bolts using an S = 14 socket wrench.When removing, light blows on the cover are allowed and significant displacements from the axis of the input shaft are not allowed in order to ensure the safety of the cuff.

- remove the oil pump 6 by unscrewing the four bolts with a socket wrench with S = 14;

- remove the primary shaft 7 (see Figure 2) from the gearbox housing 1 with the simultaneous removal of the toothed ring 1 (see Figure 10) of the 4-5 gear synchronizer.

Figure 37 - Scheme for removing the demultiplier 1 - demultiplier puller, 2 - technological stop with a size of 50x40x30 mm, 3 - M16x100 bolt, 4 - Eye-clamp, 5 - M14 bolt - 2 pcs., 6 - M14 nut - 2 pcs.

- after removing the range, the input shaft cover, the oil pump, the input shaft, save the shims to install them in the places of the initial assembly (without making special adjustments): front bearing 3 (see Figure 2) of the intermediate shaft and front bearing 3 of the secondary shaft, bearing 12 input shaft, rear bearing 24 of the secondary shaft, rear bearing 25 of the intermediate shaft;

- remove from the crankcase the outer rings of the intermediate shaft bearings and the secondary shaft rear bearing due to the longitudinal movements of the shafts, as well as the creation of vibration in the gearbox housing by frequent hammer blows on the ends of the crankcase in the areas of the bearing bores. If, after removing the demultiplier, the centering cup 18 (see Figure 2) remains in the gearbox housing, then it must be removed using a special puller.

- remove the secondary shaft assembly 16 (see Figure 2) from the box crankcase using a hoist and a sling 1.5 ... .2 meters long, made from a piece of steel rope 0 4 .. .6 mm or other durable material. The sling for lifting the secondary shaft is installed with a girth for the gear wheel of the 5th gear. Lifting the shaft out of the box is carried out without jerking with a gradual turn upward of the front end of the secondary shaft.

- remove the intermediate shaft assembly 2 (see Figure 2) using the techniques recommended for removing the secondary shaft;

When disassembling the gearbox using a wooden stand, it is recommended to remove the clutch housing after removing the range multiplier. To remove the range multiplier, place the gearbox in a vertical position with support on the clutch housing. For horizontal arrangement of the box on a wooden stand, it is recommended to use

Original for printing - Reference manual for maintenance and repair of KP type YaMZ-239Los

put wooden blocks and wedges installed in the gaps between the wooden stand and the frame

ASSEMBLY OF THE YAMZ-239 GEARBOX

Parts and assemblies of the gearbox entering the assembly must be clean, traces

scale and corrosion are not allowed. Channels (holes) for supplying lubricant in the crankcase, in the primary shaft, in the secondary shaft, in the parts of the demultiplier must be flushed with diesel fuel or machine oil and purged with overpressure air. Used parts and assemblies with permissible wear and new ones instead of parts with wear or other deviations are used for assembly.

The assembly should be carried out in conditions that provide the possibility of installing the gearbox with vertical shafts on a special stand (see Figure 33). In exceptional cases, for a one-time repair at the site of operation, it is allowed to use a wooden stand (see Figure 35) made of bars and planks.

Measurements of dimensions to determine the required thickness of the adjusting spacers of the tapered bearings of the intermediate shaft, secondary shaft, primary shaft must be made with an accuracy of 0.01 mm, at least. Measurements are made in at least three equidistant places from each other.

When calculating the dimensions of the required thickness of the shim, the arithmetic mean of these dimensions must be taken.

Shim options and sizes are shown in Table 7 below.

Table 7 - Variants and sizes of KP shims of the YaMZ-239 type

If necessary, the adjusting gaskets are modified to ensure the required size in thickness (grinded) individually for each specific place.

Assemble the gearbox in the following sequence:

- install the crankcase on a stand, securely fasten it to the plate, or install the crankcase on a support, ensuring the horizontal position of the flange to mount the gearshift mechanism;

- insert bushing 32, intermediate reverse gear 31 with roller bearing 26 into the crankcase cavity;

- install axle 28 with key 27;

- insert the intermediate shaft assembly without the outer bearing rings into the crankcase cavity with a gradual change in the position of the shaft relative to the crankcase, while the shaft is initially driven into the hole in the rear wall of the crankcase (see Figure 72);

- check that the gear rim Г of the intermediate shaft meshes with the gear rim of the intermediate reverse gear;

Original for printing - Reference manual for maintenance and repair of KP type YAME-239Los

- determine the required thickness of the shim between the end of the outer ring of the front bearing of the secondary shaft and the end of the groove for it in the primary shaft (see order above);

- start the secondary shaft without outer bearing rings and without the toothed ring of the 4th gear of the synchronizer of the 4th - 5th gear (see Figure 73);

- install the toothed synchronizer ring;

- install the outer ring of the front bearing of the output shaft;

- insert into the holes of the front wall of the crankcase alternately the installation cups of the secondary and intermediate shafts so that the shafts are centered on their bearings (see Figure 74);

- unfold the crankcase, ensuring the upper position of the rear end;

- install the outer rings of the rear bearings of the secondary and intermediate shafts;

- determine the size of the shims of the bearings of the rear secondary and intermediate shafts;

Figure 74 - Fixing the shafts in the gearbox housing of the YaMZ-239 type 1 - Bowl of the intermediate shaft, 2 - the glass of the secondary shaft, 3 - toothed ring of the 4th gear synchronizer,
4 - gear wheel of the intermediate shaft drive

- install in the demultiplier end ring 23 (see Figure 2), sun gear 21 (ensuring the position of the inner groove with a chamfer towards the main gearbox), coupling 20 with a spring ring 19 (ensuring the position of the large chamfer towards the demultiplier), bearing seat 18 with an adjusting gasket 24 (with a thickness dimension determined in accordance with the instructions given in section 8 below) and an outer ring of the rear bearing 22 (see Figure 8) of the secondary shaft;

- install the outer bearing ring of the rear 8 (see Figure 5) of the intermediate shaft into the crankcase;

- install on the outer end of the rear intermediate shaft bearing a spacer 25 (with a thickness dimension determined in accordance with the instructions given below in section 8);

- screw two pins of the guides (see Figure 75) into the holes with the M16 thread located on different sides of the main gearbox housing;

- install gasket 29 on the end face of the main gearbox housing with preliminary application of UG-9 TU 6-01-1326-86 or UG-6 TU 6-01-1285-84 sealant on both end surfaces of the gasket with a continuous strip 2.3 mm wide along the contour on the end surface of the crankcase;

- fix the eye-bracket with two M14 bolts (see Figure 37) to the range-multiplier flange;

- install the roller bearing 17 (see Figure 2) into the groove of the rear end of the secondary

- connect the demultiplier with additional parts in the order shown below to the rear end of the gearbox housing, while the outer cylindrical surface of the socket 18 must enter the hole in the rear wall of the main gearbox housing, the coupling coupling 20 must engage with the clutch of the toothed secondary shaft

Original for printing - Reference manual for maintenance and repair of gearbox type YaMZ-239Los 23 (see Figure 8), the groove of the demultiplier spacer must enter the outer ring of the intermediate shaft shaft 20;

- fix the demultiplier with bolts 30, when screwing in the bolts, significant distortions are not allowed, six bolts are screwed from the side of the gearbox housing into the threaded holes of the demultiplier spacer, and two bolts are screwed from the side of the demultiplier spacer into the threaded holes of the gearbox housing; and a spanner with size S = 22 mm, the tightening torque should be within 22.25 kgf • m.

- unfold the partially assembled gearbox, ensuring the upper position of the front end of the crankcase;

- remove the glasses fixing the intermediate 1 and secondary 2 (see Figure 74) shafts;

- install the outer race of the front bearing 7 (see Figure 5) of the intermediate

- install the primary shaft with the inner ring of the bearing, the spacer 3 and the outer race 4 of the front bearing of the secondary shaft into the hole in the crankcase of the main gearbox (Figure 3 shows the completeness of the primary shaft for installation in the crankcase);

- install the outer ring of the primary shaft bearing;

- determine the thickness of the shims of the input shaft bearing and the front bearing of the intermediate shaft (the procedure for determining the thickness of the gasket is given below in section 8), in the absence of gaskets of the required size, perform additional processing (grinding) of the gasket with the maximum thickness;

- install the oil pump 6 (see Figure 2) with an adjusting gasket 3 and a sealing rubber ring 4, ensuring the pump housing is centered along the hole in the crankcase for the intermediate shaft bearing and the connection of the drive pump shaft with the intermediate shaft;

- tighten the four bolts securing the pump to the gearbox housing, tightening torque 5.0.5.5 kgf-m;

- install the bearing cover of the input shaft with a collar, a sealing rubber ring and an adjusting gasket so that the cover is based on the outer ring of the bearing due to the recess in it;

- tighten the six bolts of the cover fastening with a torque of 5.5.5 kgf-m, before installing the bolts of the oil pump and the primary shaft bearing cover, apply UG-9 TU 6-01-1326-86 or UG-6 TU 6- sealant to the thread of the bolts 01-1285-84;

- check the amount of axial movement of the intermediate shaft using a tool (see Figure 76). Measurement should be made as follows: through the oil intake hatch in the gearbox housing, insert the measuring bar 1 and fix it on the intermediate shaft using the spacer screw 2; to the flange of the oil intake hatch, fix the bar 3 with the indicator 5, move the shaft relative to the crankcase in the direction of the axis due to the force applied to the end of the 5th gear gear, then set the indicator to zero, move the shaft in the opposite direction, while the deviation of the indicator arrow should be within 0.005.0.06 mm;

- check the correct adjustment of the bearings of the primary and secondary shafts by axial movement of one of the shafts, as well as by turning the primary shaft at a frequency of 10.15 min-1, the synchronizer couplings and the first gear and reverse gear must be in the neutral position, the locking rings must be squeezed out from ring gear cones. The axial movement of the shafts should be within 0.005.0.06 mm, and the scrolling moment of the input shaft should be no more than 0.3 kgcm;

- measurement of the movement of the primary and secondary shafts is carried out using a device (see Figures 76-78), the movement of the shafts is carried out by mounting, installing it in the gaps "b" and "g", the measurement begins after moving the primary shaft towards the secondary, and then move secondary shaft towards the primary shaft;

- in case of unsatisfactory results of checking the axial displacements of the shafts, re-adjust the bearings;

- install the gasket on the upper crankcase flange, centered on two pins;

- install the gear shifting mechanism on the upper flange of the crankcase, while all rods with forks must be in neutral position, synchronizer couplings, 1st gear and reverse gear must be in neutral position, forks must be in vertical position.

When installing the mechanism, pay special attention to the entry of the gear shift forks into the grooves of the synchronizer couplings and the first gear; installation of the mechanism is possible only after the forks are connected to the couplings;

- fix the gearshift mechanism with twelve M10 bolts with a wrench size S = 17 mm, the tightening torque of the bolts is 5.0.5.5 kgf-m;

- fix the pipeline 65 (see Figure 2) of the lubricant supply from the oil pump to the primary shaft cover with special bolts 52 with centering gaskets 53 (washers made of soft copper) on each side of both pipeline fittings, tighten the bolts with a torque of 5.0.5.5; kgf-m;

- install the clutch housing 5 on the gearbox with the centering of its outer machined surface of the cover 11 of the input shaft with a diameter of 200 mm;

- fix the clutch housing with eight bolts 50 with spanner size S = 22 mm. Install the bolts on the anaerobic sealant UG-2M TU -6-02-64-89 (not less than 0.15 g / bolt or 4.6 drops), after degreasing the bolt threads in the main gearbox housing. Tighten evenly in two stages, the initial tightening torque is 10.12 kgf-m; final - 22.25 kgf-m.

- install the clutch 10 with hose 55 on the bearing cover of the input shaft; before installing the clutch, its bearing and the cavity of the bore must be filled with Shrus-4M grease TU 38.401-58-128-95;

- fix the lubrication hose 55 with a nut 57 with a preliminary installation on the hose connection of the clip 56 with the spring 54 hooked onto the clip;

- install the shaft 8 and the fork 9 into the cavity of the clutch housing, so that the shaft with bushings 61 goes into the hole in the crankcase and into the hole of the fork, while the bushings on the shaft must be fixed with retaining rings 60, to install the shaft sleeves made of cermet use a tubular a mandrel with inner and outer diameters of 25.5 mm and 33.5 mm, respectively, with a length of 80.100 mm, when installing the shaft sleeves, avoid sharp shock loads to prevent splitting of the sleeves, the shut-off shaft sleeves are fixed against axial displacement by locking rings 60;

- install in the grooves of the holes for the shut-off shaft sleeves, respectively, the plug and the seal parts;

- lubricate the shut-off shaft bushings through the nipples until grease appears from the gaps, using the Shrus-4M grease TU 38.401-58-128-95.

Figure 77 - A device for measuring the axial play of the primary and secondary shafts 1 - dial indicator; 2 - indicator bar; 3 - adjusting sleeve; 4 - bolt М6х30; 5 - extension bar; 6 - screw М4,
7 - front cover
Note: parts 2, 3, 5 are connected by electric arc welding

Figure 78 - Installation of devices for checking the axial play of the KP shafts of the YaMZ-239 type 1 - a device for measuring the axial play of the primary and secondary shafts,
2 - a device for measuring the axial play of the intermediate shaft,
A and B - access zones of the mounting tool for sampling the gaps of the primary and secondary shafts

1. The correct operation of the gearbox and its service life are directly dependent on the culture of operation, therefore, you need to carefully consider the performance of all routine maintenance provided for in this manual.

2. The use of lubricants not recommended by this manual is not permitted.

3.To avoid damage to the demultiplier synchromesh and the main gearbox synchromesh, it is not allowed to engage gears in the main gearbox when the demultiplier shift indicator lamp is on.

4. To avoid an excessive increase in the engine crankshaft speed and increased wear of the gearbox synchronizers, do not allow the lower range in the range to be engaged at a vehicle speed above 45 km / h.

5. In order to avoid damage to the gearbox when the car is moving, it is strictly forbidden to engage the first gear when the highest range of the range is engaged.

Characteristics of gearboxes YaMZ-239

The YaMZ-239 gearbox manufactured by Avtodiesel OJSC (base model, Fig. 1) is a mechanical, nine-speed, consists of a five-speed main gearbox and a dual-band planetary range, with synchronizers in all gears, except for the first gear and reverse gear.

MAIN DIFFERENCES OF MODIFICATIONS AND EQUIPMENT OF KP FROM THE BASIC MODEL

The main differences from the basic KP model

Check point 239 YMZ - universal. It is the basis for the creation of new types of gearboxes for all types of trucks.

The gearbox includes a demultiplier (dual-band) with synchronizers (they are not available only in first gear and reverse), a mechanical speedometer drive, and an electromagnetic locking system. It is also possible to complete it with a heat exchange system, which will monitor the temperature of liquids, cooling it in the heat or heating it in the cold.

The pre-equipment of the gearbox 239 with a demultiplier will have two speeds: standard and increased.

The 239 gearbox scheme with a demultiplier hardly changes, only a more accurate speed control is possible.

In general, the checkpoint operation scheme will depend on the car brand.

The operating time of the checkpoint 239 is determined by how accurately all the conditions of the manual for its use are met. In the event of a breakdown or malfunction, it is important to use the services of a service station or try to fix the problem yourself. Operation and maintenance instructions are available on our website in the appropriate section.

The YaMZ 239 gearbox is intended for the YaMZ-7511 engines of MZKT, KrAZ, MAZ, Ural vehicles.

YAMZ-239 gearbox. Device, maintenance and repair.

This reference manual contains a description of the design of gearboxes of the YaMZ-239 type produced by Avtodiesel OJSC (Yaroslavl Motor Plant), the features of their operation, the procedure for carrying out maintenance and repairs during operation.

The reference manual is intended for engineers and technicians and other workers of road transport and repair enterprises associated with the operation and repair of cars and their components, it can be useful for students and students studying cars and their components.

The reference manual is recommended for use by subjects of the service network of JSC Avtodizel (YaMZ) as a guideline when carrying out service maintenance of YaMZ power units in terms of gearboxes and their auxiliary systems during the warranty and post-warranty periods of operation.

Spare parts for KAMAZ, VAZ, GAZ, Scania, Volvo, Man and other manufacturers.
Spare parts for trucks and cars of domestic and foreign production.

9-speed manual transmission

Transmission type. 9-speed, mechanical; a five-speed main gearbox with a dual-band planetary range, with synchronizers in all gears except first gear and reverse.

FEATURES OF THE DESIGN. there is a blocking of starting the starter when the gear is engaged; electronic speedometer sensor.

Gear shift control. Lever or mechanism for connecting a remote drive with the output of the connecting roller to the left in the main box and semi-automatic pneumatic switching of the range with automatic blocking of the lower range.

Additional power take-off. From the countershaft spur gear through the right side hatch up to 29.5 kW (40 hp); From the ring gear at the rear end of the countershaft via the PTO shaft up to 73.5 kW (100 hp). The volume of oil in the gearbox housing is 11.5 + 0'5 liters.

Additional options. The boxes can be equipped with a pressurized clutch housing.

Assembly of the gearbox is carried out on the same stand (see Fig. 128) as disassembly. Before assembly, all parts of the gearbox are thoroughly washed, dried, the channels are purged with a compressed

air. All rubbing surfaces are lubricated with oil. First, large knots are assembled.

Assembling the drive shaft. On the drive shaft 5 (Fig. 136), using a special mandrel and applying a force to the end of the inner ring of the bearing, press the ball bearing 4 complete with the retaining ring 3 until it stops, clamp the shaft in a vice, placing soft washers, tighten the ring nut 2 to failure , and then drill it into a groove on the shaft. The rotation of the outer ring of bearing 4 must be free, without jamming.

Assembling the driven shaft. A thrust washer 15, a gear 16 of the second gear are put on the shaft 14, two segment keys are placed and the spacer sleeve 17 of the synchronizer of the second and third gears is pressed against the stop. The spacer sleeve with its annular cut must face the front end of the driven shaft. The rotation of the second gear on the shaft should be light, without jamming.

On the intermediate shaft of YaMZ-236 gearboxes of release until December 1968. a gear wheel of a non-rigid design with spring damping elements was installed, the so-called damper gear. At present, this gear has been replaced by a gear of a conventional rigid design, numbered 236U-1701056. When repairing gearboxes, the damper gear should be replaced with a rigid gear that is supplied with spare parts.

The upper gearbox cover is assembled in this sequence.

First, in the cover / (Fig. 137) of the box, the rod 3 of the forks for switching the first gear and reverse gear is installed, after having installed the spring 12 and the ball // of the rod retainer; put the head 6 and the plug 13 on the rod, move the rod to the neutral position and insert two balls 15 of the lock retainer through the hole in the rod of the fork of the second and third gears. Having previously installed the spring and the ball of the rod retainer, insert the rod 5 of the shift forks of the second and third gears, put the head 7 and the shift fork 10 on the rod, insert the pin 14 of the lock, advance the rod to the neutral position and insert two balls through the hole in the rod of the fork of the fourth and fifth gears lock latch. After inserting the ball into the spring of the retainer of the rod of the fourth and fifth gears, insert the rod 4, while putting on the plug 8 of the fourth and fifth gears, and move it to the neutral position.

After that, the heads and forks of the switch are fixed with screws 9. All set screws are cotted with wire. When one of the rods moves longitudinally, the other two must be locked with a lock in the neutral position. Then they put three plugs in the grooves on the front end of the cover, distribute them, put the leash 35 for switching the first gear and reverse gear on the axle 36, insert a fuse into the leash

34 and, as such, install the axle in the hole in the cover. From the outside of the cover, a spring washer is put on the leash axle and the nut is tightened to failure. The swing of the leash on the axle should be light, without jamming. Next, the second fuse 41 is inserted into the lid, and the fuse spring 40 is inserted into the glass 39 and the glass is wrapped in the lid until it stops.After assembling the upper gearbox cover, check for the presence of clamps on all three rods and the ease of movement of the rods in the cover supports after removing them from the neutral position. The assembly of the mechanism for remote switching of the YaMZ-236 and YaMZ-236P gearboxes begins with the installation in the crankcase 25 of the mechanism of the sleeve 29 of the gear selector lock with the pin 28 and the spring 27. The sleeve is fixed in the housing with a set screw 26 with a spring washer. Then, a segment key is inserted into the groove of the gear shift shaft 16, and the intermediate shift lever 17 is put on, secured with a set screw 20, cotted with a soft wire, inserted into the body of the gear shift shaft 16, and a second segmented key into the groove of the roller, put on the gear shift lever 30, secured lever with set screw 31 and cotter it with wire.

mm. It is strictly forbidden to install thicker shims. After assembly, the roller should rotate easily without jamming. Axial clearance is allowed no more than 0.20 mm.

The assembled pump should be checked for performance and for leaks in the connections on a special stand. The newly assembled pump must have a flow rate of at least 7 l / min. If the oil pump before being installed on the gearbox has not been tested at the stand, then it should be lubricated, i.e. put the pump on the housing with the shaft end up, pour oil used to lubricate the gearbox into the suction hole, and turn the driven shaft by three four turns clockwise until oil appears in the discharge port.

Before installing the cover, check the rotation of the driven gear of the speedometer drive, which should be light, without jamming. Axial play is allowed up to 1.2 mm. The stuffing box is pressed into the cover using a mandrel shown in Fig. 139. The oil seal is pressed against the stop into the oil deflector collar with the oil scraper groove. On gearbox covers manufactured before February 1969. there was no collar with an oil drainage screw groove in front of the oil seal; the gland is installed in such a cover using the same mandrel until it stops in the cover. The front end of the gland seat ring should be flush with the inside of the bonnet. The gland should be installed in the cover using CIATIM-201 grease. Further, protecting the front bearing of the driven shaft from damage, install the drive shaft with the bearing. The retaining ring of the drive shaft bearing should fit close to the front wall of the crankcase, and the front bearing of the driven shaft should enter the drive shaft easily and freely. Shock loading is not permitted.

At the rear end of the driven shaft, fasten with a nut 7 (see Fig. 136) with a washer 8, the cardan flange 9. The nut is split. On the YMZ-236 gearboxes of the first release, a protective casing was installed on the cardan mounting flange. December 1968 The protective cover is not installed on the flange. On YAMZ-236N gearboxes since April 1971. the universal joint flange was shortened by 2 mm (from 84 to 82 mm), and the length of the spacer sleeve was increased from 26 to 28 mm. Thus, the new shortened flange can only be fitted to older gearboxes with a 28 mm bushing or a 2 mm washer.

After that, put the oil intake mesh 20 (see Fig. 126) with a gasket and the oil intake cover assembled with a magnet so that the gasket and cover do not block the oil intake channel in the box crankcase, screw in the control and drain plugs, install the power take-off hatch cover, put plugs - plugs for oil channels and through holes in the crankcase, throttle, bushing, gasket and cover 3 of the drive shaft bearing with an oil seal. In order not to damage the gland, the cover is put on only using the mandrel 7 (Fig. 140). The oil seal 3 is pressed into the cover 2 of the drive shaft using a special mandrel 7 until it stops.Before pressing in, the outer surface of the stuffing box is lubricated with a thin layer of CIATIM-201 grease.

The clutch housing is secured with bolts with washers and lock plates; the bolts lock by bending the plates on the edge of the bolts.

Then, the shaft of the clutch release fork is inserted into the hole of the crankcase, while simultaneously putting the fork 13 on the shaft (see Fig. 120), insert a segment key into the groove of the shaft and push the clutch release fork onto the key. The fork is secured to the shaft using a pinch bolt with a spring washer. On the bearing cover of the drive shaft, put on the clutch // for disengaging the clutch with the bearing, the clutch release springs, connect the clutch lubrication hose 12, fixing it in the crankcase wall, screw the grease fittings into the clutch release fork shaft supports and into the clutch lubrication hose fitting.

Having put the synchronizers, the first gear and reverse gear and the forks in the neutral position, put a cover with a gasket on the crankcase. In this case, all three forks with their paws must enter the grooves of the synchronizer couplings and into the groove of the first gear and reverse gear. The cover is secured with bolts and spring washers. Finally, a gearshift mechanism is installed. When assembling the gearbox, in order to ensure the tightness of the joints, you can use a non-drying sealing paste Sealant grade UN-25 (TU 3336-52 MHP). The paste is applied with a brush with a thin even layer on the surface of the gaskets before installing them, and also the through threaded holes are lubricated with it before installing the bolts.

The test of the gearbox is carried out on a stand providing a drive shaft speed of 1500-2000 rpm. In terms of connecting dimensions, the stand should simulate the connection between the gearbox and the engine and is equipped with a clutch and a gearshift mechanism. 5.5 liters of TS-14.5 oil with an EPO additive according to TU 38-1-173-68, heated to a temperature of 65 ° C, is poured into the gearbox.

The operation of the gearbox with any gear engaged should occur without sharp noises and knocks. Oil leakage in joints and stuffing box seals is not allowed. Gear shifting should be without great effort and jamming. With the neutral position of the gear lever at maximum revolutions of the drive shaft, it is allowed to drive the driven shaft, eliminated by a torque of no more than 1.5 kgf-m applied to the flange. The temperature of the oil in the gearbox housing during the tests should not exceed 85 ° C. The duration of the gearbox tests is at least 15 minutes.