Modern car Is a technically complex device that combines elements of microelectronics, hydraulics, electrical and other systems that require periodic maintenance. One of the components that requires special attention is the transmission. Although the unit is different long term service and high reliability, operation in poor conditions road surface can significantly reduce the working life of the entire system.
The main function that the transmission performs is the transfer of mechanical energy from the engine to the wheels, so if it breaks down, the normal movement of the car is almost impossible. Regulartransmission maintenance will ensure the stable operation of the entire system and the absence of emergency breakdowns in the most unexpected moments.
Car transmission maintenance
Fulltransmission service carried out in accordance with the recommendations of manufacturing plants, which for each specific brand vehicle may differ.Transmission service helps to identify deviations in the operation of the device from the normal mode. This can happen for various reasons, the main ones being:- irregular service;
- poor quality manufacturing or component parts;
- unsatisfactory quality of the road surface;
- violation of operating rules;
- use of non-original oils and other Supplies;
- incompetenttransmission service ;
- physical deterioration.
Our car service is one of the leaders in the North-Eastern Administrative District of the city of Moscow in restoring the performance of the transmission and other vehicle components. Professional maintenance and repair of transmission by our specialists are carried out in the shortest possible time while maintaining High Quality works. We are located in the North-East Administrative District not far from the Altufyevo, Bibirevo and Medvedkovo metro stations. We have equipped convenient approaches to our repair boxes. Positive reputation in the Moscow car services market, reasonable prices and high quality of restoration and diagnostic work - these are our priorities when working with clients.
The main symptoms of transmission faults
During the operation of the car, a number of signs may appear that indicate a malfunction in the gearshift system:- Difficulty shifting gears The main reason for this phenomenon is a low oil level in the system, its unsatisfactory quality, a poorly tuned cable of the gearshift mechanism or a cable for adjusting the clutch.
- the smell of burning. This could be a sign of overheating in the transmission oil, which is used to lubricate and cool numerous system components. Low level oil in the system is one of the prerequisites for overheating.
- Availability extraneous noise at neutral speed. In most cases, this indicates mechanical wear of parts: intermediate gear, bearings, and other mechanisms.
- seizing the clutch of the clutch system. In this situation, the clutch disc is not disconnected from the flywheel, even when the clutch pedal is depressed. Quite often this happens due to poor adjustment of the clutch pedal travel.
- oil leak. Refers to one of the main signs of the need for repairs. A lack of lubricant in the gear shift system is the main cause of serious breakdowns.
- increased vibration. If, when changing gears, the car starts to throw, the ride is disturbed and the clarity of the changes is reduced, then it's time to contact a car workshop for a thorough diagnosis.
- violation of the switching speed. The drivetrain is designed to shift smoothly and accurately, so delays in shifting to another speed may indicate the presence of technical problems from undercarriage car.
Car transmission repair
Transmission repair is a complex process consisting in carrying out special technical operations that will help restore the service life of all transmission elements. For high-quality diagnostics of the car, we have equipped our auto repair center with all necessary equipment allowing high accuracy in minimum terms determine the location of the breakdown and possible reasons its occurrence.
Our specialists quickly carry out the incoming performance check vehicle, which allows you to add up the overall picture of the general technical condition of the car within a couple of hours. The personnel of our company are exclusively highly qualified specialists who have great experience in diagnostics, repair and maintenance of transmission.Capital transmission repair involves a complete disassembly of the system into component parts and assemblies. This allows the transmission to be inspected for deformations and physical wear. After replacing or eliminating the failed transmission components, the entire system must be assembled and reassembled on the vehicle.
Repair of transmission units
The design of the transmission is a complex device containing the following main components:- gear box;
- clutch;
- friction disc.
The gearbox can be of three types:
- mechanical;
- automatic;
- robotic.
Each of these types of mechanisms has common features: presence of lubricant in the system, presence of gears and switching devices. Maintenance experts recommend gearboxes to be carried out after every 25,000 kilometers. This will make it possible to timely detect even minor malfunctions, which over time can become the main cause of an accident.
For vehicles with a manual transmission, a clutch is characteristic, which serves to disconnect the engine shaft from the wheel drive during gear changes. The clutch rod is in most cases a cable that needs to be adjusted periodically. The main reasons for clutch failure are:- extreme driving style;
- untimely gear shifting;
- a sharp start in overdrive.
The friction disc ensures reliable adhesion between the engine shaft and the wheel drive shaft. The workmanship of the friction disc directly affects its service life. Thus, branded products produced by manufacturing plants serve an order of magnitude longer than their inexpensive counterfeits.
To ensure a high quality of repairs, each time after the restoration of the transmission performance, the oil is changed. This measure allows you to extend the service life of many units and parts of the machine and avoid costly emergency repairs.Maintenance of the transmission in our workshop
Transmission repair by our specialists it is produced in the following order:- preliminary thorough diagnostics using modern equipment;
- dismantling from a regular place with detailed disassembly;
- thorough troubleshooting and inspection of all units and parts;
- preparation of a defective statement;
- agreement with the client on the cost of work and the list of services;
- restoration of the integrity and operability of faulty assemblies and parts;
- phased assembly of the device;
- installation of the transmission in a regular place;
- adjustment and check of transmission in working mode.
The cost of transmission repair services can vary in a wide range, depending on the individual nature of the breakdown and the complexity of its restoration.
Recommendations for correct use
To significantly extend the service life of the car's transmission and eliminate its unexpected breakdown, experts recommend regularly carrying out a number of measures:- daily check the operation of the clutch, the absence of oil leaks and the smooth operation of the gearbox;
- check the oil level in the clutch drive after passing 10,000 kilometers;
- adjust the clutch pedal travel after 20,000 kilometers;
- when the oil level drops, the shortage should be filled up to the recommended value as soon as possible.
Let's talk about the maintenance of the gearbox - how to check and change the oil in the gearbox, and when to prepare for the repair.
The gearbox makes it possible to change the traction force on the driving wheels of the machine by engaging gears with a different number of teeth. In addition, it provides reverse gear and long-term separation of the engine (together with the clutch) from other transmission units when the vehicle is parked or when it is inertia.
What do you need to know?
Before each departure of the machine, check the absence of oil leaks and noise in the operating gearbox, ease of engagement and shifting of all gears. When driving, check the absence of noise and knocking in various operating modes. Change the gearbox oil after the first 2000-3000 km. The oil should be changed immediately after the ride, before it has cooled down.The sequence of actions is as follows:
- remove the drain and filler screw plugs;
- drain the oil from the gearbox housing into a container;
- flush the gearbox by filling it with 0.5 - 0.7 liters of liquid mineral oil starting the engine and letting it run for 3-5 minutes for Idling in the neutral position of the gears of the gearbox;
- stop the engine and drain the flushing oil;
- Fill in fresh oil up to the lower edge of the filler hole.
It is necessary to check the oil level when the gearbox is cold, when all the oil has drained into its crankcase.
During repairs, you have to disassemble the gearbox, check the suitability of its parts, replace damaged and worn parts, and then assemble it back. Before disassembly, it is removed from the car by unscrewing the clutch housing mounting bolts, and the oil is drained from it.
When troubleshooting the gearbox, it is necessary to remove it from the car and subsequent complete or partial disassembly. It requires special tools and accessories. Therefore, it is recommended to troubleshoot the box in an auto service.
Transmission units: clutch, gearbox (GB), hydromechanical transmission (GMT), cardan transmission, drive axles account for 15 ... 20% of failures and 20 ... 30% of material and labor costs for their elimination. This is due to the fact that the main working parts of the transmission are under the influence of high specific alternating loads most of the time.
The main clutch malfunctions are: lack of free play of the clutch pedal of functional pads; loosening of springs; incomplete disengagement of the clutch due to large free travel; skewed levers or warpage of the driven disc; heating, knocking and noise due to the destruction of the shutdown bearing; loosening of the rivets of the disc lining; breakage of damper springs; wear of the spline connection.
Driveshaft malfunctions include: shaft runout, increased gaps in the joints, which is accompanied by vibration, knocking and noise during operation, especially when shifting gears in acceleration mode.
Typical malfunctions manual transmission, transfer case, main gear are: self-shutdown of the transmission due to misalignment of the drive, wear of bearings, teeth, splines, shafts, retainers; noises and knocks when shifting gears due to synchronizer malfunctions; increased vibrations, heating, backlash due to wear or breakage of gear teeth, wear of bearings, misalignment of gearing of gear pairs, low level or lack of lubrication in gearboxes.
The main malfunctions of a hydromechanical transmission include: non-engagement of gears when the car is moving due to failure of electromagnets, jamming of the main spool, failure of hydraulic valves, misalignment of the system automatic control gear shifting; inconsistency of the gear shift points due to misalignment of the automatic gear change system or malfunctions of the power and centrifugal regulators low oil pressure in the main line due to wear of parts oil pumps or internal leaks transmission oils; increased oil temperature at the drain from the torque converter due to warpage or wear of the clutch discs.
For front wheel drive passenger cars additional malfunctions may occur: damage to the covers covering the constant velocity joints (SHRUS); deformation of drive shafts; wear of the hinges themselves.
In general diagnostics of the transmission, mechanical losses due to the spinning of the driving wheels are determined by the traction stand, the smoothness of the gear engagement, noise and knocks during the operation of the transmission elements, and the amount of their heating are assessed.
With element-by-element diagnostics, the technical condition of each of the units is determined.
Technical condition The clutch is quite fully determined by the amount of free travel of the pedal, the completeness of the clutch release and its slipping. Pedal free play is measured with a ruler or special devices type KI-8929. In this case, the pedal is pressed by hand, moving it from its initial state to the occurrence of effort on the pedals. For most cars, it should be within 15 ... 45 mm (cars with mechanical or hydraulic drive clutches). If the free play does not match, it is adjusted by changing the gap between the ends of the pressure levers and release bearing, for which a threaded adjustment unit is provided in the drive rod. The completeness of the clutch release is assessed by the ease of gear engagement.
Clutch slip is determined when the car is operating under load on the traction bench using an electronic stroboscope included in the ignition system circuit or using a stroboscope connected to the injector of the first cylinder (for a diesel engine).
At the time of filing high voltage pulses are applied to the spark plug of the first cylinder or injection by a fuel injector to the stroboscope, leading to discrete flashes of the stroboscopic device lamp, carried out synchronously with rotation crankshaft engine. In the absence of clutch slipping, the driveshaft, illuminated by the strobe lamp flashes, will appear stationary, as it rotates with crankshaft as one whole. If the propeller shaft rotates perceptibly in the light of the strobe lamp, then the clutch slips. It is advisable to carry out such a check together with the assessment of the power properties of the car. The hydraulic or pneumatic clutch is assessed for tightness.
The technical condition of the gearbox is determined by its thermal state, noise, knocking, vibrations, by the total angular play in each gear and by inspection with an endoscope.
The thermal state of the gearbox is determined using special thermometers after the vehicle returns from the line so that the transmission units do not cool down. The temperature should not exceed 35 ... 50 ° С. Large values indicate the presence of wear or insufficient oil in the gearbox housing. When diagnosing noise and vibration parameters, stethoscopes are used. This method combined with listening to the characteristic noises of the transmission elements when simulating the movement of a car on traction stands at low load. In this case, the ease of gear shifting, places of increased heating, etc. are additionally revealed.
The total angular backlash in gears is determined using a dynamometer-backlash (Figure 2.44). With the help of clamp 1, it is attached to the flange of the universal joint cross, connected to the gearbox output shaft. Press the handle 9 with a force of 15 ... 25 N × m, fixed on the scale 8 of the dynamometer and note the position of the bubble of the liquid level 4 on the angular scale 5. Then press the handle 9 with the same force in the opposite direction so that the gaps are also selected along the liquid level and scale 5 determine the total angular clearance. The check is carried out with sequential engagement of all gears. The value of the total angular backlash in gears should not exceed 6 ... 10 °. Large values of the backlash indicate the presence of wear in the gear pairs.
Diagnostics of hydromechanical transmissions is carried out at the traction stand with the setting of the necessary speed and load modes - acceleration, braking, steady motion in each gear. In this case, portable devices are used that are connected to the electromagnets of the first and second gears, to the oil supply line from the main spool to the torque converter lock-up valve. It also determines the moments of gear shifting in terms of speed with a smooth "acceleration" of the car on the unloaded rollers of the stand. In this case, the switching points are determined by the vibrations of the speedometer needle.
1 - screw terminal; 2 - movable jaws; 3 - crosspiece flange; 4 - liquid level; 5 - angular limb; 6 - spring; 7 - arrow of the dynamometer; 8 - dynamometer scale; 9 - handle
Figure 2.44 - Diagram of a dynamometer-backlash
The GMF mechanisms are adjusted using a special screw, changing the position of the main spool to ensure the required modes automatic switching gears (for example, for the GMF of the LiAZ bus during acceleration with a fully open throttle switching from a downshift to a direct one should take place at a speed of 25 ... 30 km / h, a torque converter lock - at a speed of 35 ... 42 km / h). The stroke of the end of the longitudinal control rod of the power regulator control and the clearance in the control mechanism of the spools of the peripheral valves are also regulated in order to reduce the wear of the double clutch discs during operation.
The cardan drive is diagnosed by radial runout. At the same time, one is posted drive wheel and using the device, the radial runout is determined (Figure 2.45). It is equal to the difference between the maximum and minimum values indicator readings when turning cardan shaft 360 ° (to do this, manually rotate the suspended wheel). The permissible runout value for trucks is 0.9 ... 1.1 mm, for cars - 0.4 ... 0.6 mm. Wear in hinges and spline joints is assessed visually by their relative displacement when the propeller shaft is manually turned in both directions. There should be no perceptible backlash and knocking. The total angular backlash can also be measured using a backlash dynamometer. In this case, one end of the cardan transmission must be pinched (for cars such as GAZ, ZIL, the parking brake is used). Its value should not exceed 2 ... 4 °.
Drive axles are diagnosed using the same parameters and the same means as manual transmissions. The total angular backlash for single main gears should be no more than 35… 40 °, for double - 45… 60 ° (when checking, the gearbox must be in neutral).
1 - cardan shaft; 2 - indicator tip; 3 - a tripod with stops; 4 - indicator of linear movements
Figure 2.45 - Diagram of the device for checking the runout of the propeller shaft
These works can be carried out in parallel with preventive operations. So with TO-1 it should be checked free run clutch pedals and the tightness of the hydraulic or pneumatic drive. The gearbox checks the operation of the gearshift mechanism when the vehicle is stationary. According to the GMF, the correctness of the adjustment of the control mechanism for the peripheral spools is checked. The cardan transmission is used to check the backlash of the hinged and spline joints, the condition of the intermediate support. In addition, during TO-1, the fasteners of the transmission elements and the tightness of the gearbox and drive axle connections are checked. With TO-2, in addition, according to the GMF, the correctness of the adjustment of the gear shift modes, the oil pressure in the system and the serviceability of the oil temperature sensor are checked, along the drive axle - the fastening of the flange nut of the main gear drive gear (with the cardan shaft removed).
When servicing the front wheel drives, they are limited to inspecting them and listening to noises and knocks in the CV joints when the wheels are spinning. When a malfunction is detected, unusable elements ( rubber covers, SHRUS) are replaced. When replacing the SHRUS, grease SHRUS-4 (ULi 4/12-d2) is put into it, which is not replenished until the next replacement.
Work on the restoration of transmission units is performed in the unit section after they have been dismantled from the vehicle. The clutch is removed after dismantling the gearbox, as a rule, together with the casing, having previously disconnected its drive. After removal, the pressure and driven discs are cleaned.
The driven disc is defective for wear of friction plates and runout. Replace worn-out pads with new ones. When the end runout of the driven disk is more than 1 mm, it is straightened. For all other malfunctions, the driven disc is replaced. The pressure disk is discarded when it is significantly worn out or other defects. Clutch installation is carried out in the reverse order of disassembly. To center the driven disc relative to the flywheel, use a special slotted mandrel or an auxiliary input shaft gearbox by inserting it into the spline of the driven disk and the crankshaft flange bearing. Then the clutch cover is finally tightened to the flywheel. Moreover, it is necessary to tighten gradually and consistently in 2 ... 3 receptions. If the clutch is hydraulically operated, it is pumped to remove air, and then the pedal free travel is adjusted.
When repairing the gearbox, the oil is drained from it. Then the gearbox is removed from the car, subjected to external cleaning and washing, and delivered to the aggregate section. Initially, the gearbox cover with the gearshift mechanism is removed. To press out the input shaft, use a special tool (Fig. 2.46).
Figure 2.46 - Device for pressing out the input shaft bearing
The output shaft bearing together with the shaft is pressed out with a hammer using a mandrel. Intermediate shaft pressed out with a puller. For disassembly intermediate shaft special devices are also used. After final disassembly, all parts are washed in kerosene or detergent solution (if there is an installation for washing parts) and defective. Worn out elements are replaced.
Gearbox assembly is carried out in the reverse order of disassembly. All gaskets are recommended to be installed on rubber # 80. After installation on the car, the control panel is filled with transmission oil according to the lubrication chart.
The cardan transmission is also repaired in the unit compartment, having previously subjected it to external cleaning and washing. It is advisable to disassemble the hinges using a special tool (Figure 2.47). It is carried out in two steps. First, one of the forks is installed on the supports and the needle bearings are pressed out of it. Then the propeller shaft is turned 90 ° and the bearings are pressed out of the second fork. The same puller can be used to install bearings, which are pre-loaded with 4 ... 5 grams of grease No. 158 (ULi - PG 4 / 12-1) or Fiol-2M (ILi 4/12-d2). If the hinges have grease nipples, then they are lubricated with a solid blower after assembly. When disassembling the splined joint of the cardan transmission, markings are made so that its balance is not disturbed during assembly.
a - extrusion of bearings from the sliding fork; b - pressing out the bearings from the propeller shaft plug
Figure 2.47 - Disassembly tool cardan joint
Disassembly rear axle truck it is advisable to carry out also after removing it from the vehicle as an assembly. In passenger cars, as a rule, only the gearbox is removed. After external cleaning and washing, the mounting bolts are unscrewed and the main gear is removed. Removal of the bearings of the drive gear shafts and the bearings of the differential cup is carried out using a puller (Figure 2.48). After disassembly, all parts are subjected to washing and troubleshooting. Worn out elements are replaced.
Before assembly, all bearings are lubricated with Litol-24 (MLi 4 / 12-3) and pressed using mandrels. For the normal installation of the gearing of the gear teeth, oil paint is applied to them in a thin layer along the contact patch. Then the shaft of the driving bevel gear is turned in one direction and the other, braking the driven gear by hand.
1 - screw; 2 - traverse; 3 - screed; 4 - screed cheek; 5 - capture; 6 - tip
Figure 2.48 - Removing the bearing of the differential cup
The position of the contact patch is used to assess the nature of the engagement (Table 2.6).
The contact patch is adjusted by axial movement of the driven and driving gears, for which the installation of adjusting shims is provided in the design of the main transmission. The degree of tightening of the bearings of the pinion drive shaft is checked using a dynamometer (Fig. 2.49).
| Position of the contact patch on the wheel | Ways to Achieve Correct Engagement gear wheels | Direction of movement of gears | |
| Forward motion | Reverse | ||
| Correct contact | |||
| Slide the toothed wheel towards the pinion. If this results in too little lateral clearance between the teeth, move the gear | |||
| Move the toothed wheel away from the pinion. If this results in too large a lateral clearance between the teeth, move the gear | |||
| Move the gear to the wheel. If the side clearance is too small, move the gear back | |||
| Move the gear away from the wheel. If the side clearance is too large, move the gear | |||
1 - cover; 2 - bearing housing; 3 - leading bevel gear; 4 - vice; 5 - dynamometer; 6 - flange; 7 - nut
Figure 2.49 - Checking the tightening of the bearings of the drive gear shaft
The torque of the drive gear shaft should be no more than 1.0 ... 3.5 N × m, when tightening the flange mounting nut 7 with a torque of 200… 250 N × m. Adjustment is also carried out using shims, provided by the design main gear. After final assembly, the main gear is installed on the car and transmission oil is poured into the rear axle housing according to the lubrication chart.
clutch box gimbal transmission
Preparation for work and the procedure for carrying out maintenance
Preparation for maintenance consists in carrying out necessary work related to bringing the car into proper form. The required list of work for each type of maintenance is described in the next section of the manual. Maintenance is carried out in points or areas of maintenance or in specially equipped rooms that provide the maintenance personnel with the necessary working conditions.
According to the frequency, volume and labor intensity of the work performed, maintenance is divided into the following types:
Daily maintenance (EO);
First maintenance (TO - 1);
Second maintenance (TO - 2);
Seasonal maintenance (CO).
The frequency of the first and second maintenance depends on the category of vehicle operating conditions, determined by the type and condition highways... Characteristics of the categories of operating conditions and the frequency of maintenance - 1 and maintenance - 2 are carried out in table 1
Table 1
When daily maintenance(EO) check the clutch, gearbox, cardan shafts and consist in cleaning from dirt, tightening bolted joints, adjusting and lubricating. After driving on muddy roads, clean the hole in the lower part of the clutch housing. Timely lubricate the clutch release bearing through the grease cup located on the right side of the clutch housing.
When TO - 1 every 4,000 km, or annually when the noise level is high, the oil level in the gearbox is checked if a leak occurs.
To check the oil level in the manual transmission, the vehicle must be parked on inspection pit, clean the area around the filler plug, unscrew and remove the plug. The oil should reach the bottom edge of the hole. If you need to check the oil level, you can insert a clean piece of flexible wire inside the box.
At a reduced level, you need to top up special oil for mechanical boxes gear. It is undesirable to exceed the level, as it may flow out over the edge of the hole.
In case of replacement, it is necessary to drain the oil while hot, by unscrewing the drain plug and first placing a container of the required volume under the gearbox. After that, the drain plug should be reinstalled, replacing the sealing washer, if necessary (it is advisable to change the washer each time the plug is unscrewed). Then fill in new oil and replace the filler plug.
When TO - 2 the clutch mechanism is checked is carried out with the clutch pressure plate removed in the following sequence:
1. Installed between the plate and the pressure plate, the template of the driven disk in the form of a ring with a thickness of 9.5 mm. The assembled pressure plate is fixed to the casing on the plate with six bolts.
2. Adjustment is carried out by screwing and unscrewing the stop bolts until the size 51.5 ± 0.75 is obtained. mm- distance of bolt heads from the surface of the plate (Fig. 13). The difference in the distance from the plate to the bolt heads should not exceed 0.2 mm.
3. The lever bolts are locked after adjustment, the edge of the lever is bent into the groove of the bolt shank, as shown in (Fig. 14)
Maintenance of the clutch release drive is reduced to adjusting the free travel of the release pedal, maintaining the level working fluid in the reservoir of the main cylinder of the hydraulic drive.
Service front axle is to maintain required level oil in the crankcases and its timely change, checking the seals, timely detecting and eliminating I axial clearances in the gears of the main drive, periodically cleaning the safety valve and tightening all fasteners.
Removing the flange 35 (fig. 12) is made with the same bolts I with which it is attached.
Fill only the recommended oil into the housings of the final drive and wheel reduction gears and change it in strict accordance with the lubrication table.
Make sure that the oil level in the crankcases is at the lower edges of the filler holes.
The oil is drained out through the drain holes located on the »bottom of the crankcases, while unscrewing the filler plugs as well.
Fig. 12.
1 - clutch cover; 2 - pressure spring; 3 - pressure disk; 4 - thrust bolt; 5 - pull-off lever
Fig. 13.
For seasonal maintenance (CO). Before the summer season technical operation replace the oils in the gearbox, front and rear axles with the flight grade, similarly to replace the oils in the winter.
Plan - synopsis
industrial lesson
Topic: Car maintenance.
Lesson topic: Technical maintenance of mechanisms and transmission units.
The purpose of the lesson: to form in students the basic concepts of maintenance of mechanisms and units of transmission of cars.
Educational purpose: instill in students a conscientious attitude towards the study of the material presented.
Occupation type - a lesson in presenting new material.
2. The main part of the lesson
Study questions:
The main malfunctions of mechanisms and transmission units of cars.
The main work performed during the maintenance of mechanisms and transmission units of vehicles.
1. Inappropriate driving, first of all, is reflected in the state of the transmission. Sudden jerks, overloading of mechanisms during operation, poor lubrication lead to breakdowns and malfunctions that permanently disable the car.
Clutch malfunctions. In the clutch mechanism, malfunctions may occur: incomplete engagement (the clutch slips) or incomplete disengagement (the clutch leads), as well as a sharp engagement of the clutch. A faulty clutch makes it difficult to drive and thus affects driving safety.
When the clutch slips , the torque from the engine shaft is not fully transmitted to the drive wheels (especially when the vehicle is moving with a load on an uphill).
With an increase in the speed of the engine crankshaft when the clutch pedal is released, the car does not move at all, or its speed increases very slowly; sometimes the car jerks and the smell of burnt friction linings and driven discs is felt in the cab. Reasons for slipping clutch: lack of clearance between the clutch bearing and the engaging levers when the clutch pedal is released, as a result of which the driving disc is not fully pressed against the driven; to eliminate this malfunction, it is necessary to check and adjust the free travel of the clutch pedal; oiling of the clutch discs; this malfunction occurs when the clutch bearing is excessively lubricated when grease flows through the rear main bearing of the crankshaft; in this case, the friction force decreases sharply and the discs * slip. To eliminate this malfunction, the clutch must be disassembled, rinsed thoroughly, and the friction linings must be cleaned with a steel brush or rasp; wear of friction linings; if the wear of the pads is small, the malfunction is eliminated by adjusting the clutch pedal free play; if the linings are heavily worn, they must be replaced with new ones;breakage or loosening of pressure springs; the springs must be replaced.
The clutch is not completely disengaged . A sign of this malfunction is the inclusion of a gear, accompanied by a sharp metal grinding of the gears of the gearbox, and the possibility of their breakdown is not excluded. Such a clutch malfunction can occur for the following reasons:large clearance between the thrust bearing of the release clutch and the inner ends of the release levers; eliminate this malfunction by adjusting the free travel of the clutch pedal;skew or warping of the driven discs and, as a result, an unequal gap between the discs (and in some places there is no gap); this malfunction most often occurs when the clutch overheats after slipping and is eliminated by replacing warped discs;
breakage of friction linings, as a result of which the torn lining is wedged between the driven and driving discs and does not allow the clutch to be completely disengaged; the clutch must be disassembled and the linings replaced;skew pressure plate; when the clutch is disengaged, the drive disc continues to partially press against the driven disc. Such a malfunction occurs when the inner ends of the clutch release levers are not in the same plane; in this case it is necessary to adjust the position of the clutch release levers.
The clutch engages sharply despite the slow and smooth release of the pedal; the car starts jerkily. Such a malfunction can be in the event of a sticking of the release clutch on the guide sleeve. When the clutch pedal is released, the clutch will move unevenly along the bushing, when the force of the springs overcomes the binding of the clutch, it will quickly move, abruptly freeing the release levers, and the discs will quickly compress. Sharp engagement of the clutch can also be caused by small cracks on the drive discs after they are overheated. To eliminate the indicated faults, replacement of the corresponding parts is required.
Transmission malfunctions and transfer case. A number of malfunctions can occur in the gearbox: chipping or breakage of gear teeth, spontaneous disengagement of gears, noise of gears during operation, simultaneous engagement of two gears and difficult gear shifting. All this worsens the conditions for safe traffic.
Chipping and breakage of gear teeth can occur as a result of a sharp start-off from a loaded car, with inept gear shifting and with a faulty clutch. Operation of the gearbox with broken gear teeth is unacceptable, as this can lead to the destruction of the entire gearbox.
Spontaneous shutdown gears are possible due to uneven wear of the gear teeth and synchronizer couplings, incomplete gear engagement and wear of the locking device.
Gear noise when shifting gears occurs due to a malfunction or improper clutch adjustment and inept engagement. Loud noise gears when driving is caused by lack of lubrication, high wear of gears or bearings.
Simultaneous engagement of two gears occurs as a result of wear of the balls or the rod of the locks.
Difficulty shifting gears happens due to clogging or corrosion of the holes under the sliders, jamming of balls in the channels of the retainers, wear of bearings and gear hubs, which leads to their distortion.Oil leaks out of the gearbox if gaskets are damaged, oil seals are worn and cracks appear. The driver himself can replace the gasket, clean the hole under the sliders and clips and add oil to the gearbox housing. The rest of the faults are eliminated in the workshop by restoration or replacement of parts.
Gimbal malfunctions andmain gear, differential and axle shafts ... As a result of vehicle operation in the cardan drive, wear of bearings, cardan crosspieces and sliding spline coupling, bending or twisting of the cardan shaft is possible. Disconnecting the propeller shaft can lead to an accident.
In the main gear and differential the following are possible: wear or breakage of the gear teeth; wear of the differential cross and boat bearings; wear or damage to oil seals; oil leakage in the rear axle housing connections. In the axle shafts, their twisting, wear of the splines, the loosening of the nuts of the axle shaft flange to the hub, or breakage of the studs are possible. A symptom of a driveline malfunction are jerks and shocks when starting off or shifting gears on the move. Shaft runout during rotation indicates that the shaft is bent.
Main gear malfunctions are externally manifested by significant noise in the rear axle housing when the vehicle is moving.
Driveshaft malfunctions are eliminated by restoring or replacing worn parts. The bent shaft must be corrected. Small clearances in the bearings and between the teeth of the final drive are eliminated by adjustments that must be made by experienced mechanics. If the parts of the final drive and differential are heavily worn, they must be replaced.
Worn axle shaft oil seals can lead to the ingress of grease into brake drums and the failure of the brakes, therefore, worn out oil seals must be replaced. In the event of a breakdown of the teeth of the gears of the main drive and differential, independent movement of the car is impossible.
2. Basic clutch maintenance work.
EO. Check the operation of the clutch mechanism by starting the vehicle and shifting gears while driving.
TO-1. Check pedal free play (and, if necessary, adjust it), conditionandRetaining spring attachment. Lubricate (according to the lubrication schedule) the clutch pedal shaft and the clutch release bearing. Check the clutch function.
TO-2. Check the full and free travel of the clutch pedal and the action of the return spring, the operation of the clutch drive and, if necessary, adjust the clutch and drive.
The bearing of the clutch release on GAZ-53A and ZIL-130 cars of the first issues is lubricated from an oiler filled with grease, for which it is necessary to screw the oiler cover two or three turns. On cars ZIL-130 ( latest issues) grease is added to the bearing of the clutch release at the factory and is not added during operation. Clutch faults make it difficult to drive, distract the driver from observing the road, and interfere with the movement of other vehicles.
Basic maintenance work on the transmission and transfer case.
EO. Check the operation of the transmission while driving.
TO-1. Check and, if necessary, tighten the gearbox mount; if necessary, add oil to the level. Check the operation of the transmission after servicing.
TO-2. Carry out an in-depth inspection of the transmission. Check and, if necessary, tighten the gearbox mount to the clutch housing and gearbox housing cover. Check and, if necessary, tighten the fastening of the bearing cover of the driven and intermediate shafts.Top up or replace gearbox oil (per lubrication schedule). Oil change, lubrication of units and joints must be carried out with the engine off. If the driver or locksmith is under the car, a sign "Do not start the engine!" Must be posted in the cab (on the steering wheel). The car must be reliably braked so that it cannot move spontaneously.
Basic work on the maintenance of the cardan and main gears, differential.
EO. Check the operation of the cardan and main gears while driving
TO-1. Check and, if necessary, fasten the flanges of the universal joints and axle shafts. Secure final drive housing covers. Check the oil level in the drive axle housing and top up if necessary. Lubricate cardan joints and outboard bearing(according to the lubrication schedule).
TO-2. Check for any play in the cardan joints. Fasten the flanges of the axle shafts, cardan shafts and the support bearing to the frame. Check the tightness of the drive axle connections. Check the oil level or replace the oil in the drive axle housing. Lubricate the driveline splined coupling (according to the lubrication schedule). The cardan crosspieces are lubricated with summer or winter transmission motor-tractor oil according to the lubrication chart (in the latest releases of ZIL - 431410 and KamAZ vehicles with grease 158 or US-1) using a syringe with a tip through an oiler until the oil starts to come out of the hole,
closed by a valve on the side opposite to the grease nipple (for ZIL cars - 431410 of the latest releases and for KamAZ - from under the oil seals of all four crosspieces). The splined cardan coupling is lubricated with US-1 or 1-13 grease (GAZ-53A and ZIL-130) at every third TO-2. Lubricate the splined coupling in moderation to prevent the plug from being pushed out. In GAZ-53A cars, the intermediate support bearing must be lubricated with grease 1-13 at each TO-1, and in ZIL-130 - at the second TO-1. On dusty and muddy roads, lubrication times are halved.
To lubricate the main gear of ZIL-431410 cars, summer and winter automotive transmission oil (TAP-15, TAP-10) is used, GAZ-53A - TS-14.5 oil with an additive "Chloref-40", KamAZ - TS P -15k or TAP-15V.
The oil level in the drive axle crankcase is checked after 3000 km of run. The oil level should be at the edge of the filler hole. The oil in the drive axle crankcase is changed according to the lubrication chart and when the operating season changes. Long work main gear and thrust bearings largely depends on the quality and purity of the oils. The use of other oils is not allowed. Before filling with fresh oil, the drive axle crankcase must first be flushed with liquid oil or kerosene. To do this, after draining the used oil (the oil should be drained heated immediately after work), 2-3 liters of liquid oil or kerosene are poured into the crankcase, the drive axle is lifted onto the goats, the engine is started and, having switched on direct transmission, it is allowed to work for 1-2 minutes, after then drain the oil or kerosene, tightly close the drain plug and fill in fresh grease at the level of the filler (control) hole. Oil is poured into the crankcase of the rear axle of cars in the amount of: ZIL-431410 - 4.5 liters, GAZ - 53A - 8.2 liters, KamAZ - 6 liters in each drive axle.
Control questions.
List the main clutch malfunctions.
List the main faults in transmissions and transfer cases.
List the main faults cardan transmission, final drives and differentials.
List the main work carried out during the maintenance of the clutch.
List the main work carried out during the maintenance of transmissions and transfer cases.
List the main work carried out during the maintenance of cardan drives, final drives and differentials.
