Bs428 Transmission Workshop Mannual 20156

山推 BYD4208 变速箱维修手册

BS428 Transmission Service Manual

Foreword This service manual mainly covers the removal and refitting process, service technology and standard requirements for BS428 transmission (also applies to BYD4208 series transmission), so as to help service personnel understand the method of removing and refitting it and to lay a solid technical foundation for them concerning proper fault diagnosis and troubleshooting. This service manual mainly includes the following: Chapter 1 Introduction This chapter mainly describes precautions for servicing transmission, explains the meaning of each symbol which are included in the following text and specifies the tightening torque for plain bolts. Chapter 2 Transmission system This chapter mainly describes the gearshift principle of transmission, the transmission line of each gear, and the operation and maintenance of oil supply line and transmission. Chapter 3 Removal of transmission This chapter describes how to remove each part properly and the relevant precautions in the process. Chapter 4 Refitting of transmission This chapter describes how to refit each part properly and the relevant precautions in the process. Chapter 5 Service tools for transmission This chapter describes special tools required in the process of servicing transmission. Chapter 6 Fault diagnosis and troubleshooting This chapter describes common faults and troubleshooting of the transmission.

Note The specifications of parts covered by this Manual may be subject to modification due to the improvement of this product, and no further notice will be given upon such modification, so please contact SDLG for the latest data.

BS428 Transmission Service Manual

Contents 1 Introduction ................................................................................................................ 1 1.1 Safety precautions ............................................................................................. 1 1.2 Description of signs ........................................................................................... 2 1.3 Tightening torque table for plain bolts .............................................................. 3 2 Transmission system .................................................................................................. 5 2.1 Description of transmission............................................................................... 5 2.2 Basic parameters of transmission & torque converter assembly ...................... 6 2.3 Structure and principle of transmission............................................................. 6 2.3.1 Structure of transmission ........................................................................... 6 2.3.2 Shifting principle of transmission.............................................................. 7 2.3.3 Gear transmission lines .............................................................................. 8 2.3.4 Structure and principle of shifting clutch ................................................ 10 2.3.5 Structure and principle of automatic emptying valve (oil drain valve) ... 11 2.4 Oil supply system ............................................................................................ 13 2.4.1 Structure and working principle of transmission & torque converter oil supply system .................................................................................................... 13 2.4.2 Introduction to oil supply system main components ............................... 14 2.5 Transmission Operation and Maintenance ...................................................... 18 2.5.1 Installation and Application Notices for Transmission ........................... 18 2.5.2 Maintenance of Transmission .................................................................. 18 3 Removal of Transmission ......................................................................................... 20 3.1 Removal of assembly components .................................................................. 20 3.1.1 Removal of oil filler pipe and filter ......................................................... 20 3.1.2 Removal of parking brake assembly ....................................................... 21 3.1.3 Removal of transmission control valve ................................................... 22 3.1.4 Removal of breather and cover plate ....................................................... 23 3.1.5 Removal of input flange .......................................................................... 23 I

BS428 Transmission Service Manual

3.1.6 Removal of oil sump ................................................................................ 23 3.1.7 Removal of high/low gearshift fork mechanism ..................................... 24 3.1.8 Removal of output shaft ........................................................................... 24 3.1.9 Removal of three sets of clutch gear shafts ............................................. 26 3.2 Removal of assembly ...................................................................................... 28 3.2.1 Removal of transmission control valve ................................................... 28 3.2.2 Removal of three sets of clutch gear shaft assemblies ............................ 30 4 Refitting of Transmission ......................................................................................... 34 4.1 Refitting of assembly....................................................................................... 34 4.1.1 Refitting of clutch shaft assembly ........................................................... 34 4.2 Refitting of assembly components .................................................................. 38 4.2.1 Assembly of three sets of gear shafts ....................................................... 38 4.2.2 Refitting of input flange and rear end cover ............................................ 40 4.2.3 Assembly of countershaft and reverse gear shaft rear end cover ............ 41 4.2.4 Assembly of output shaft ......................................................................... 42 4.2.5 Assembly of high/low gearshift fork mechanism .................................... 42 4.2.6 Assembly of oil sump .............................................................................. 43 4.2.7 Assembly of transmission control valve .................................................. 43 4.2.8 Assembly of breather and cover plate ...................................................... 44 4.2.9 Assembly of parking brake assembly ...................................................... 44 4.2.10 Assembly of oil filler pipe and filter ...................................................... 45 5 Service Tools for Transmission ................................................................................ 46 6 Common Fault Diagnosis and Troubleshooting ....................................................... 47

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BS428 Transmission Service Manual

1 Introduction 1.1 Safety precautions Important safety notice Service and maintenance is essential to the safe operation of vehicle. This Manual mainly states the related techniques on how to remove and refit the transmission assembly properly. To prevent relevant personnel from being hurt, this Manual takes

as safety sign. With

regard to precautions attached with this sign, it is required to do operation carefully. In case of potential hazard, first take into account the safety of yourself, and meanwhile take necessary protective measures. Safety notice In the process of refitting and removal, improper operation technique will lead to part damage, service life reduction and deterioration in operating performance, and in addition, it may cause unsafe factors. Therefore, please read related content in this manual carefully before refitting and removing any part. 1. The parameters, figures and content covered by this manual apply to product of standard configuration. As regard to variant, please consult our coMPany or relevant data. 2. In repair workshop, a separate or special area shall be set for placing removed parts, corresponding tools and parts shall be placed at appropriate area, and the operation area shall be kept clean and free of oil dirt and other contaminant. Do not smoke at any place other than the specified area. Never smoke during operation, and it is required to have fire extinguishing device. 3. When welding operation is necessary, it shall be done by a trained and experienced welding worker. During welding, it is required to wear and use appropriate protective equipment such as welding gloves, baffle, goggles, work cap and overall. 4. Before removing transmission & torque converter assembly, make sure to clean the dirt from its external surface so as to prevent parts from being contaminated during removal. 5. During operation, do wear safety shoes and safety helmet. Do not wear inappropriate work coat. The work coat must be buttoned. When striking parts with a copper rod, safety goggles shall be

1

BS428 Transmission Service Manual worn. 6. Petrol, kerosene and water-based oil cleaner can be used to clean the removed parts. 7. To use a crane or other hoisting equipment, first check the slings for damage. It is required to use hoisting equipment with sufficient lifting capacity. During lifting operation, do lift slowly at appointed position so as to prevent parts from striking against each other. Do not work under the lifted parts. 8. When two or more people are required to work simultaneously, they shall be in agreement with the same operation procedure in advance to avoid accident due to out of step conditions. 9. Make sure to keep all tools properly and get familiar with their operating methods. 10. To align one hole with another, do not get your hand or finger into the holes. As regards to parts requiring direct assembly with hand, always pay attention to the holding position and check it for risk of crushing. 11. Make sure to perform inspection on the removed parts. The part of which the defect has already affected the performance must be replaced. 12. After assembling all parts, no interference is allowed. 13. When assembling the oil seal and seal ring, if they have to pass key groove, screw hole and step, then corresponding protective measures shall be taken so as to avoid damaging them. 14. In the process of refitting parts, the tools used shall match corresponding threaded fasteners so as to prevent the fasteners from being damaged. 15. To tighten joint body and plug screw, do not use pneumatic wrench. Be sure to rotate them to some extent with hand, and then tighten them with torque wrench of corresponding specification to the required torque value. 16. When draining oil from transmission, be sure to unscrew the drain plug slowly so as to prevent oil from spurting out.

1.2 Description of signs To make this manual fully play its roles, the signs in Table 1-1 are used in respect of critical safety and quality requirements.

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BS428 Transmission Service Manual Table 1-1 Sign Item

Remarks During operation, pay special attention to safety.

Safety

During operation, pay special attention to safety because of inside pressure. During

operation,

pay

special

attention

to

technical

Note requirements so as to ensure operation quality. Weight of component or device and removal & refitting modes. Weight

Pay attention to the selection of sling and the postures during operation.

Tightening torque

Pay special attention to the tightening torque of component during assembly.

Application

Points requiring the application of adhesive and grease.

Oil and water Add a certain amount of oil, water and fuel. Draining

Position for draining oil or water, as well as draining amount.

1.3 Tightening torque table for plain bolts Table 1-2 Nominal diameter of bolt (mm)

Yield Strength strength class

6

8

(N/mm2)

10

12

14

Tightening torque (Nm)

8.8

640

9~12

22~30

45~59

78~104

124~165

10.9

900

13~16

30~36

65~78

110~130

180~210

12.9

1080

16~21

38~51

75~100

131~175

209~278

Nominal diameter of bolt (mm)

Yield Strength strength

16

18

20

class (N/

Tightening torque (Nm)

3

22

24

BS428 Transmission Service Manual mm2) 8.8

640

193~257

264~354

376~502

521~683

651~868

10.9

900

280~330

380~450

540~650

740~880

940~1120

12.9

1080

326~434

448~597

635~847

864~1152

1098~1464

Yield Strength

strength

class

(N/

Nominal diameter of bolt (mm) 27

30

33

36

39

Tightening torque (Nm)

mm2) 8.8

640

952~1269

1293~1723

1759~2345

2259~3012

2923~3898

10.9

900

1400~1650

1700~2000

2473~3298

2800~3350

4111~5481

12.9

1080

1606~2142

2181~2908

2968~3958

3812~5082

4933~6577

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BS428 Transmission Service Manual

2 Transmission system 2.1 Description of transmission BS428 transmission is a fixed shaft, constant mesh and power gearshift transmission, which is mainly used for LG933L and LG936L loader. In the transmission system of LG933L and LG936L, the engine is directly connected to the torque converter via an elastic plate so as to realize output power, and torque converter is connected via the propeller shaft to front input flange of the transmission where speed change and torque increase happens such that the power can be transmitted to front and rear drive axles via front and rear propeller shafts respectively. BS428 transmission mainly consists of input shaft assembly, countershaft assembly, and reverse gear shaft assembly, high-low gear sliding sleeve as well as its control mechanism and many pairs of constant mesh gear, etc.

Fig. 2-1 1.Breather 2.Transmission control valve 3.Reverse gear shaft 4. Input shaft 5.Countershaft 6.Oil drain plug 7.High-low gearshift fork 8.Output shaft 9.Filter 10.Oil filler pipe 11.Parking brake

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BS428 Transmission Service Manual

2.2 Basic parameters of transmission & torque converter assembly Table 2-1 Item

Parameters/description Single-stage three-element turbine hydraulic

Type torque converter Torque ratio Torque converter

3.25

Oil pressure at torque converter inlet 0.5~0.6 (MPa) Oil pressure at torque converter 0.2~0.3 outlet (MPa)

Transmission

Type

Fixed-shaft power shift

Gears

4 gears in front and 2 in the rear

Transmission working pressure 1.1~1.5 (MPa)

2.3 Structure and principle of transmission 2.3.1 Structure of transmission BS428 transmission includes three sets of normally opened clutches, which are closed by hydraulic fluid, and they control the 1st gear, 2nd gear, 1st reverse gear respectively, or the 3rd gear, 4th gear and 2nd reverse gear when the shift fork is set to a higher gear. The one installed on the input shaft is the 1st gear clutch; the power from torque converter is transmitted to input shaft via a connecting flange and the input shaft is the total input of transmission. The one installed on the countershaft is the 2nd gear clutch, and the countershaft can transmit the power from the 1st gear and the reverse gear to the output gear. The one installed on the reverse gear shaft is the reverse gear clutch which can make the loader drive backwards when it is engaged.

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BS428 Transmission Service Manual

View from input terminal

Input shaft

Reverse gear shaft Countershaft

Output shaft

Fig. 2-2 1. Reverse gear shaft clutch

2. Input shaft clutch 3. Intermediate gear shaft clutch

2.3.2 Shifting principle of transmission The transmission’s gearshift mechanism is a mechanically-operated one, with the gear controller of BS428 transmission shown in Fig.2-3. This gear controller includes two gearshift levers: 1. direction control handle (see Fig. on the left), which connects to the gearshift control valve stem on the transmission via a flexible shaft; 2. high/low speed control handle (see Fig. on the right), which connects to the shift fork on the transmission via a flexible shaft. The gear controller operates the clutches of different gears by controlling the speed change valve. The working conditions of clutches are shown in table 2-2.

Fig. 2-3 Gear selector 7

BS428 Transmission Service Manual Table 2-2 Working conditions of clutches Ⅰ Ⅰ

Ⅲ

Shift fork

√ √

Ⅱ Ⅲ

Ⅱ

√

Ⅳ

√

Ⅰ

√

Ⅱ

√

2.3.3 Gear transmission lines The power of the hydraulic torque converter is transmitted to the transmission via the input shaft flange installed on the part of the right end of the input shaft that extends outside the transmission box. The input shaft assembly, reserve gear shaft assembly and immediate shaft assembly connects with the transmission box in the same way. Both ends of them are supported on the transmission box and big end cap by conical bearings. Adjust the clearance of conical bearing during assembly, to avoid damage to the bearing. The gears on the output shaft assembly, reverse gear shaft assembly, countershaft assembly and output shaft are constantly meshed with each other. There are three stop positions (HI, N, LO) in the high-low gear sliding sleeve which is refitted on the output shaft. The high gear position corresponds to a high speed; the low gear position corresponds to a low speed. When the sliding sleeve stays at the neutral position, no power will be output by the transmission. Caution: Never shift the high-low gear sliding sleeve before the transmission is in the neutral gear after the loader is stationary, otherwise, impacting and crashing of the gears may occur.

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BS428 Transmission Service Manual 1. 1st (3rd) gear transmission line 3rd gear (when the shift fork is set to the right

Reverse gear shaft

high speed gear): input→Z3→Z4→Z7→Z9→output

Input shaft Input

1st gear (when the shift fork is set to the left shaft Countershaft

low speed gear): input→Z3→Z4→Z7→Z5→Z8→Output

Output shaft

Fig. 2-4 2. 2nd (4th) gear transmission line 4th gear (when the shift fork is set to the right

Reverse gear shaft

high speed gear): input→Z3→Z6→Z7→Z9→ Input shaft

output 2nd gear (when the shift fork is set to the left

Countershaft

low speed gear): input→Z3→Z6→Z5→Z8→ output

Output shaft

Fig. 2-5 3. 1st （2nd） reverse gear transmission line 1nd reverse gear (when the fork is set to the left Reverse gear shaft

low speed gear): input→Z3→Z1→Z2→Z7→ Z5→Z8→output

Input shaft 2nd reverse gear (when the fork is set to the right high speed gear): input→Z3→Z1→Z2→

Countershaft

Z4→Z7→Z9→output Output shaft

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BS428 Transmission Service Manual Fig. 2-6

2.3.4 Structure and principle of shifting clutch 1. Structure The housing and gear of the hydraulic clutch is fixed together with bolts, and the gear connects to the external spline of the propeller shaft via the internal spline, all of which consist of the driving or driven part of the clutch. The inner part of the clutch consists of piston, outer friction lining, inner friction lining, oil seal ring, return spring, outer end cover, retaining ring, etc. The driving friction lining of the clutch connects to the clutch housing via the external spline, and the driven friction lining of the clutch connects to the external spline of the gear via the internal friction lining. Another gear is supported on the propeller shaft by the bearing and can rotate with respect to the propeller shaft. The outer friction linings in three sets of clutches are copper based powder metallurgy friction linings (6 PCS for each). The internal friction linings are made of 65Mn (5 PCS for each), with 0.5 mm concavity. When assembling, the convex surface shall face the piston end and make sure to rotate the friction linings manually after assembly for inspection.

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BS428 Transmission Service Manual

Fig. 2-7 1. Constant mesh gear 2. Centrifugal emptying valve 3. Clutch housing 4. Piston 5. Driving friction lining 6. Driven friction lining 7. Driven gear 8. Spring 9. Piston ring 10. Cylinder oil inlet passage 11. Lubricating oil passage 12. Seal ring 2. Working principle When working: the transmission oil from the transmission control valve flows through the oil passage in the transmission box and the big end cap and to the cylinder via the inlet end cover and clutch shaft that will make the piston move forward, compress the driving and driven clutch plates, and output the power via the driven gear that has been integrated with the clutch housing. When stop working: The pressure oil will be cut off; the transmission oil in the cylinder returns via the oil port; the piston returns via the return spring; the driving and driven clutch plates separates and the gear idles.

2.3.5 Structure and principle of automatic emptying valve (oil drain valve) After the clutch cylinder cut off the oil supply, the clutch housing will continue to rotate with the shaft under the action of inertia force, and the transmission oil in the cylinder will move from the 11

BS428 Transmission Service Manual inside to the outside under the action of centrifugal force which will generate pressure at the circumferential edge of the cylinder and a thrust for the poison return, therefore hindering the rapid separation of the clutch. In order to remove the centrifugal pressure from the oil inside the rotating cylinder, an automatic emptying valve shall be set on the clutch housing. When the clutch is engaged

When the clutch is released

Fig. 2-8 1 Piston 2 Clutch cylinder 3 Steel ball When the clutch is engaged: The pressure oil flows into the cylinder and flows out from the oil drainage hole via the pore passage between the steel ball and the pore. At this point, pressure difference will be formed at the front and the back of the steel ball. Under the action of this pressure difference, the steel ball will be pushed to the oil drainage hole to cover it. When the oil drainage stops, the oil pressure in the cylinder will rise. When the clutch is released: The cylinder connects with the return oil passage to release the pressure. At this point, the steel ball will no longer be pushed by the pressure oil and will move outward under the action of the centrifugal force, then, the oil drainage hole will open. The oil in the cylinder flows out from the oil drainage hole via the pore passage between the steel ball and the pore, which will help the quick return of the cylinder piston.

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BS428 Transmission Service Manual

2.4 Oil supply system 2.4.1 Structure and working principle of transmission & torque converter oil supply system 1. Structure of oil supply system The oil supply system is an important component of the hydro-mechanical transmission system, which generally consists of transmission pump, transmission control valve, oil filter, radiator, oil pan and pipeline, etc.

Fig. 2-9 Composition of oil supply system 1. Relief valve 2. Secondary filter 3. Transmission pump 4. Torque converter 5. Radiator 6. Speed change valve 7. Oil pan 8. Primary filter 2. Working principle of oil supply line When the pump impeller of the torque converter is running, the driving gear will drive the operation of the oil pump to suck oil from the tank and output the pressure oil, which will flow into the torque converter combination valve. The torque converter combination valve consists of transmission pressure valve, inlet pressure valve and constrictor. The working oil to the combination valve ensures sufficient oil for operation first and then is transmitted to the torque converter via the transmission pressure valve under the action of the transmission pressure valve. The oil pressure for 13

BS428 Transmission Service Manual transmission control and the oil pressure at torque converter inlet are controlled by the transmission pressure valve and inlet pressure valve, with oil pressure of 1.1~1.5 MPa and 0.5~0.6 MPa respectively. If the oil pressure at torque converter inlet exceeds the setting value of the inlet pressure valve, the valve port will open and the oil will spill out for oil spray of the transmission and the torque converter. Torque converter outlet pressure valve will keep the pressure at torque converter outlet within 0.05~0.15 MPa. The oil from the outlet pressure valve will flow through the radiator to the transmission lubrication system. Inlet pressure valve Torque converter combination valve

Transmissi on pressure valve

Torque converter

Reverse gear Neutral gear 1st and 3rd gear 2nd and 4th gear Cooler Lubrication

Shower 1st and 3rd gear clutch

2nd and 4th gear clutch

Reverse gear clutch

Fig. 2-10 Schematic diagram for the oil supply of transmission & torque converter system

2.4.2 Introduction to oil supply system main components 1. Structure and working principle of hydraulic torque converter YJ315LG-1 hydraulic torque converter is a single-stage single-phase three-element hydraulic torque converter. This series of torque converter as shown in Fig. 2-11 consist of energy conversion elements (impeller, turbine, guide pulley), power input/output elements (elastic plate，wheel cover, turbine shaft, output flange), fixed supporting element (housing), hydraulic parts and other accessories, etc.

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BS428 Transmission Service Manual

Fig. 2-11 Structure and schematic diagram of torque converter 1. Elastic plate 2. Turbine 3. Impeller 4. Guide pulley 5. Guide pulley seat 6. Turbine shaft 7. Output flange. (1) Power input part The drive plate, wheel cover and impeller constitute the power input part of the torque converter. The wheel cover connects with the drive plate via rubber damping block or elastic plate, and the drive plate connects with the engine flywheel housing via screws. When the engine is running, the flywheel will drive the rotation of wheel cover via the drive plate. The wheel cover is firmly connected to the impeller with bolts and sealed at the joint surface with O-rings. One end of the input part is supported on the center hole of the diesel engine flywheel housing by the shaft end of the wheel cover, and the other end is supported on the guide pulley seat by the bearing of impeller. YJ315LG-1 torque converter has also been equipped with PTO port. A part of power from the diesel engine is directly transmitted to the pump shaft gear via the transfer gear refitted on the impeller and drives the operation of gear pump by the pump shaft, etc. (2) Power output part The turbine, driving shaft, driving gear, output gear and output shaft together constitute the power output part of the torque converter. The turbine output shaft is supported at two points. That’s, the left end is supported on the torque converter wheel cover by needle roller bearing, and the right end is supported on the torque converter housing by ball bearing. The power from turbine output shaft is

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BS428 Transmission Service Manual transmitted via driving gear to the output gear with which the driving gear is meshed, and then to the output shaft by the output gear. (3) Fixed supporting part of guide pulley Guide pulley is fixed on the guide pulley seat via the splined joint, and the guide pulley seat is fixed on the torque converter housing with screws. (4) Sealing part of circulating circle YJ315LG-1 hydraulic torque converter uses three kinds of seals: ●

O-ring is used at the joint of wheel cover and impeller to prevent the leakage of liquid in the

circulating circle along the joint. ●

Alloy cast iron seal ring is used between the impeller hub and the guide pulley seat to prevent

the leakage of oil at the bearing seat. ●

Skeleton oil seal is used at the middle part of flywheel housing and the impeller hub. Note that

the lips of the skeleton oil seal shall face to the incoming flow when assembling. 2. Transmission control valve The transmission control valve is mainly composed of speed change valve and power shut-off valve, etc. When pulling the speed change valve lever outwards to the limit, the reverse gear will be engaged, and when pushing it inwards, neutral gear, 1st gear and 2nd gear will be engaged successively. The valve body has also been equipped with power shut-off valve, which will shut off the power oil to the transmission during braking to ensure more reliable braking performance.

Fig. 2-12 Transmission control valve 16

BS428 Transmission Service Manual 1. Power shut-off valve 2. Main pressure measuring port 3. Speed change valve oil inlet 4. Speed change valve lever 5. 1st and 3rd gear lubricating oil passage 6. 1st and 3rd gear pressure oil passage 7. 2nd and 4th gear pressure oil passage 8. 2rd and 4th gear lubricating oil passages 9. Reverse gear lubricating oil passage 10. Reverse gear pressure oil passage 11. Oil sprayer port 12. Cooling oil port (2) Relief valve The relief valve is mainly composed of transmission pressure valve and torque converter inlet pressure valve, etc. The speed change valve controls the transmission control pressure (1.1~1.5 MPa); the torque converter inlet pressure valve controls the torque converter inlet oil pressure (0.5~0.6 MPa). The relief valve is equipped with an oil passage which can be used to lubricate the torque converter internal gear. When the oil supply pressure in the system is too high, the overflow valve in the relief valve will open and release pressure via the pressure relief vent.

Fig. 2-13 Relief valve 1. Pressure adjusting bolt 2. Pressure relief vent 3. Lubricating oil port of torque converter internal gear 4. Torque converter oil inlet 5. Overflow valve 6. Transmission control valve oil inlet 7. Relief valve oil inlet 8. Torque converter inlet oil pressure adjusting bolt

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BS428 Transmission Service Manual

2.5 Transmission Operation and Maintenance 2.5.1 Installation and Application Notices for Transmission (1) When installing transmission, ensure the input share the same axis with the torque converter output and the transmission output share the same axis with the input of front/rear axle. (2) Transmission, after installed to the vehicle, shall be filled with about 45L of 6# hydraulic transmission oil from oil filler, and the oil level shall be checked 5 min after starting the engine, which shall reach to the level of oil dipstick. Before and after working every shift, always check the oil level in the transmission carefully. (3) The gear change in transmission from forward gear to reverse gear or vice versa as well as between high and low gears must be carried out after parking, but the change between 1st and 2nd gear or between 3rd and 4th gear can be done while driving. (4) Attention shall be paid to maintain the operating oil pressure at 1.1~1.5MPa during transmission operation, and the outlet oil temperature of torque converter shall be generally not more than 105°C and will not exceed 115°C in the short run, together with the

Fig. 2-14

oil temperature at the transmission oil sump not larger than 100°C. (5) Each control handle and mechanism shall be flexible without seizure, and gearshift must be accurate with obvious tactility. (6) When depressing the brake pedal with engine throttle full open, the vehicle shall not move. (7) Appropriate adjustment must be done to parking brake to make sure it will work reliably.

2.5.2 Maintenance of Transmission (1) Change oil in the transmission of new vehicle for the first time after the vehicle travels for 100 h and thereafter perform this operation every 500 h. The oil to be filled shall be 6# (8#) hydraulic transmission oil with filling amount of about 38L; the oil level shall be checked within 5 min after 18

BS428 Transmission Service Manual the engine is started and then runs at idling, and the level of oil dipstick shall apply. Before and after working every shift, always check the oil level in the transmission carefully. (2) Attention shall be paid to maintain the operating oil pressure at 1.1~1.5MPa during transmission operation, and the outlet oil temperature of torque converter shall be generally not more than 105°C and will not exceed 115°C in the short run. (3) New transmission, after installed to the vehicle, shall experience 12 h running-in, 2 h for each gear, and the load during which shall not exceed 70％ of rated load. Meanwhile, note the oil temperature, oil level and the fastening of bolts. After the period of running-in, wash transmission oil sump and the oil filter screen. (4) The gear change in transmission from forward gear to reverse gear or vice versa as well as between high and low gears must be carried out after the vehicle is stopped, but the gear change between 1st and 2nd gear or between 3rd and 4th gear can be done while the vehicle is running.

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BS428 Transmission Service Manual

3 Removal of Transmission 3.1 Removal of assembly components Preparation for removal: (1) Fully clean the mud and dirt on the transmission. (2) Remove drain plug to drain transmission oil. Hydraulic transmission oil: about 45L. (3) Prepare a stable transmission mounting bracket. Transmission: about 200Kg

3.1.1 Removal of oil filler pipe and filter

1.

Remove oil dipstick and the bolts fastening oil filler pipe and transmission body, and then disassemble oil filler pipe and O-ring. NOTE:

Protect O-ring.

Fig. 3-1 1 Oil dipstick 2 Oil filler pipe 3 Bolt

20

BS428 Transmission Service Manual 2.

Disassemble filter housing, and remove O-ring, 6 bolts, filter cover and shim.

Fig. 3-2 1 Filter 3.

Take filter element out.

Fig. 3-3 1 Filter element

3.1.2

Removal

of

parking

brake

assembly 1.

Disassemble the bolts connecting parking brake and transmission body to take down the parking brake.

Fig. 3-4 1 Parking brake 2 Fixing bolt 21

BS428 Transmission Service Manual 2.

Disassemble the lock plate and fixing bolts from rear front output flange; remove pressure plate and O-ring.

Fig. 3-5 1 Lock plate 2 Bolt 3.

Remove output shaft flange, brake caliper & disc and dust cover with hands. Disassemble the bolts connecting oil seal cover and transmission body, remove oil seal cover and adjusting shim and take out oil seal from oil seal cover.

Fig. 3-6 1 Oil seal cover 2 Oil seal 3 Output shaft flange 4 Dust cover 5 Brake caliper & disc

3.1.3 Removal of transmission control valve 1.

Disassemble the bolts connecting transmission control valve and transmission, and then remove upper paper washer, bottom plate and lower paper washer in turn.

Fig. 3-7 1 Bolt 2 Transmission control valve

NOTE: ●

Ensure

cleanness

and

protection

removing the transmission control valve. 22

after

BS428 Transmission Service Manual ● Protect sealing surface and gasket.

3.1.4 Removal of breather and cover plate 1.

Disassemble breather and take out flap, copper pipe and 5 Labyrinth gaskets.

Disassemble connecting bolts from the cover plate to remove paper washer. Fig. 3-8 1 Bolt 2 Cover plate 3 Breather

3.1.5 Removal of input flange 1.

Disassemble round nuts from input shaft with a

special socket to remove round nut washer, washer, input flange and dust cover.

Fig. 3-9 1 Round nut 2 Round nut washer 3 Washer

3.1.6 Removal of oil sump 1.

Lay

transmission

body

sideways,

and

disassemble the bolts connecting oil sump and transmission body to remove the oil sump.

Fig. 3-10 1 Bolt 2 Oil sump

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BS428 Transmission Service Manual

3.1.7 Removal of high/low gearshift fork mechanism 1.

Disassemble the iron wire on high/low gearshift fork mechanism, unscrew fastening screws and remove fork shaft and the fork.

Fig. 3-11 1 Iron wire 2 Fastening screw 3 Fork shaft 2.

Unscrew screw plug and washer, remove steel balls and spring and then disassemble oil seal.

Fig. 3-12 1 Bolt

3.1.8 Removal of output shaft 1.

Disassemble lock plate, unscrew the fixing bolts of rear output flange, remove pressure plate and O-ring and then take out the output shaft flange, dust cover and oil seal by hand. NOTE:

Fig. 3-13 1 Lock plate 2 Bolt 3 Pressure plate 4 Output shaft flange

Protect O-ring.

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BS428 Transmission Service Manual 2.

Unscrew the bolts connecting output rear end cover to transmission body, disassemble output rear end cover and take it out together with the whole output shaft backwards.

Fig. 3-14 1 Bolt 2 Output rear end cover 3.

Remove bearing, gear, high/low gear sliding sleeve, spacer ring and thrust ring from the shaft. NOTE:

Gear wheel can be taken out from the bottom hole of the transmission body.

Fig. 3-15 1 Output shaft 2 Thrust ring 3 Gear (output shaft high gear) 4 High/low gear sliding sleeve 5 Gear (output shaft low gear)

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BS428 Transmission Service Manual

3.1.9 Removal of three sets of clutch gear shafts 1.

Lay transmission body flat with the big end cap surface up, disassemble 3 oil inlet end covers and remove washers. Remove all seal rings on the three sets of clutch gear shafts.

NOTE: Fig. 3-16 1 Input shaft end cover 2 Reverse shaft end Safekeep the seal rings. cover 3 Intermediate gear shaft end cover 2.

Remove all external oil seal sleeves inside each cover.

Fig. 3-17 1 External oil seal sleeve 3.

Firstly use jackscrew to jack up big end cap, secondly screw two hoisting bolts into the mounting holes of the end cover, and finally operate the crane and disassemble the big end cap to remove 3 bearing cups wherein. About 15kg. NOTE:

Fig. 3-18 1 End cover 2 Hoisting bolt 3 Bearing cup

The hoisting operation shall be done slowly.

26

BS428 Transmission Service Manual 4.

Take out input shaft assembly vertically. NOTE:

Tap lightly on the rear end when it is hard to take the shaft out.

Fig. 3-19 1 Input shaft assembly 5.

Take out countershaft assembly and reverse shaft assembly in turn.

Fig. 3-20 1 Reverse shaft assembly 2 Countershaft assembly 6.

Erect transmission body, disassemble hexagon bolts and stop plates on 3 small end covers at the front and unscrew adjusting screws.

Fig. 3-21 1 Stop plate 2 bolt 3 Adjusting screw

27

BS428 Transmission Service Manual 7.

Disassemble fixing bolts of the end cover to remove the end cover.

8.

Remove 3 paper washers, 2 adjusting rings, one oil seal (input shaft) and 3 bearing cups separately.

Fig. 3-22 1 Bolt 2 End cover 3 Adjusting ring 4 Paper washer

3.2 Removal of assembly 3.2.1 Removal of transmission control valve 1.

Unscrew the plug and shim from valve stem locating lock pin and take out spring and steel ball.

Fig. 3-23 1 Plug

28

BS428 Transmission Service Manual 2.

Disassemble snap rings at the front and rear of the valve stem, push forward valve stem, and squeeze out 2 oil seals and adjusting washers at the front of the valve holes.

Fig. 3-24 1 Snap ring 3.

Then push backward the valve stem, squeeze out 2 oil seals and adjusting washers at the rear end of the valve hole and take out the valve stem.

Fig. 3-25 1 Oil seal 2 Adjusting washer 3 Valve stem 4.

Disassemble the screw plug at the front end of brake valve stem and take out spring seat, O-ring and spring.

Fig. 3-26 1 Screw plug

29

BS428 Transmission Service Manual 5.

Disassemble screw plug from the rear end of valve hole, remove O-ring, and push out brake valve stem and leather cup.

Fig. 3-27 1 Screw plug 2 O-ring 3 Leather cup 4 Brake sliding valve

3.2.2 Removal of three sets of clutch gear shaft assemblies NOTE: ● The removal of input shaft assembly shall be carried out from the front end of shaft to the rear end. The removal of reverse gear shaft and countershaft assemblies shall be carried out from the rear end of shaft to the front end. ● The method of disassembling countershaft and reverse gear shaft assemblies is similar to that of input shaft assembly, and the only difference lies in the direction of clutch. Moreover coMPared with the input shaft assembly, the countershaft assembly has one more gear and the reverse gear shaft assembly one more shaft sleeve. Take input shaft assembly as example to introduce the disassembling procedure, and the others will not be repeated here.

30

BS428 Transmission Service Manual 1.

Disassemble connecting bolts and stop pad from shaft end to remove shaft end baffle.

Fig. 3-28 1 Bolt 2 Stop pad 3 Shaft end baffle 2.

Remove internal oil seal sleeve and 2 piston rings on it.

Fig. 3-29 1 Piston ring 2 Internal oil seal sleeve 3.

Remove bearings from both ends of the shaft and shaft sleeve from the front end of the shaft.

Fig. 3-30 1 Shaft sleeve 2 Bearing

31

BS428 Transmission Service Manual 4.

Remove clutch external drum from the shaft and disassemble 8 bolts and 4 stop pads as well as a gear wheel.

Fig. 3-31 1 Clutch external drum 2 Bolt 3 Stop pad 4 Gear wheel 5.

Disassemble automatic emptying valve (oil drain valve) base and steel ball on the clutch housing.

Fig. 3-32 1 Emptying valve 6.

Disassemble retainer ring and take out external end cover from the clutch. Take out friction lining: steel disc and wafer.

Fig. 3-33 1 Retainer ring 2 External end cover

32

BS428 Transmission Service Manual 7.

Remove retainer ring from housing internal hub with special tools.

8.

Disassemble spring seat, spring and piston.

9.

Disassemble oil seal ring from the piston.

Fig. 3-34 1 Special tools 2 Shaft elastic retainer ring 3 Spring 4 Piston

10. Remove O-ring from the housing internal hub.

Fig. 3-35 1 Oil seal ring 11. Press

pinion

out

from

the

shaft

and

disassemble the snap rings at both ends and 2 bearings.

Fig. 3-36 1 Pinion

33

BS428 Transmission Service Manual

4 Refitting of Transmission 4.1 Refitting of assembly NOTE: Wash all parts before refitting.

4.1.1 Refitting of clutch shaft assembly NOTE: Three sets of clutch assemblies are of similar structure. Take input shaft assembly as example to introduce refitting procedure and the others will not be repeated here.

1.

Assemble steel ball and automatic emptying valve (oil drain valve) base.

Fig. 4-1 1 Automatic emptying valve 2.

Assemble O-ring on the housing internal hub.

3.

Assemble oil seal ring on piston, apply clean oil and put the piston into the housing. NOTE:

● When installing oil seal ring, the sealing surface shall be placed toward pressure oil surface. ● The oil seal ring is made of rubber and shall be Fig. 4-2

free of damages caused by crush during assembly.

1 Oil seal ring

● The opening width of piston ring shall be within 0.05~0.1mm.

34

BS428 Transmission Service Manual 4.

Put lower spring seat, spring and upper spring seat in the internal hub in turn and use special tools to compress the spring in order to assemble retainer ring.

Fig. 4-3 1 Special tools 2 Retainer ring 3 Spring seat 4 Spring 5.

There are 6 clutch driving plates in all, which are friction linings made of copper based powder metallurgy, and 5 driven plates made of steel with 0.5 mm concavity; make sure to put the concave surface towards piston end while refitting.

Fig. 4-4

NOTE:

1 Outer friction lining 2 Internal friction lining

● The number of outer friction linings for the three sets of clutches is 6. ● The number of internal friction linings for the three sets of clutches is 5. 6.

Assemble 11 friction linings to the housing in the sequence of outer gear, inner gear and outer gear

Outer friction lining

as shown in Fig. 4-5. NOTE: ● If abrasion that occurs during the usage of outer

Internal friction lining

friction lining is more than 2/3 in the depth of Fig. 4-5

pattern

groove,

replacement

is

required

immediately. ● Replace the corresponding friction lining only 35

BS428 Transmission Service Manual and make sure its number and refitting order is correct. 7.

Assemble external end cover and snap ring.

8.

Assemble the pinion with snap ring and 2

Fig. 4-6 1 Retainer ring 2 External end cover

bearings to the shaft in place.

Fig. 4-7 1 Bearing 2 Retainer ring 9.

Align gear wheel with the cylindrical pin on the clutch housing, fasten them with bolts and meanwhile assemble 4 stop pads to avoid looseness.

Fig. 4-8 1 Gear wheel 2 Bolt 3 Stop pad 36

BS428 Transmission Service Manual 10. Lay clutch flat and insert the pinion after aligning the teeth of internal gear friction linings with a screwdriver.

Fig. 4-9 1 Pinion 11. Turn left and right the pinion continuously until the spline of the pinion is inserted into the internal tooth of driven plate, insert input shaft to ensure the clutch is installed in place and assemble 2 bearings on both ends of the shaft. NOTE: When the length of the extending gear on the Fig. 4-10 1 Shaft sleeve 2 Bearing

spline shaft is equals to the width of shaft sleeve, it shows that the clutch is installed in place; otherwise, it means that the internal teeth of some driven plates deviate and are not engaged with the pinion. 12. Assemble 2 piston rings to internal oil seal sleeve. NOTE: ● Piston ring is made of cast iron with greater brittleness, so it needs to be installed with even force to avoid damage. ● The openings of two seal rings need to be

Fig. 4-11 1 Piston ring

2 Oil inlet passage

staggered, and also have a distance from oil inlet

37

BS428 Transmission Service Manual 3 Internal oil seal sleeve

passage. 13. Assemble internal oil seal sleeve to shaft. NOTE: ● Internal oil seal sleeve shall be installed to shaft by heating evenly in oil at the temperature of 100~150°C. ● Wear heat insulation gloves while refitting, and the picture is only for reference.

Fig. 4-12 1 Internal oil seal sleeve 14. Install shaft end baffle, stop pad and bolts.

Fig. 4-13 1 Shaft end baffle 2 Stop pad 3 Bolt

4.2 Refitting of assembly components 4.2.1 Assembly of three sets of gear shafts 1.

Lay transmission body flat, put the assembled reverse gear shaft assembly to the mounting position in the transmission body and then put in countershaft assembly. NOTE:

Fig. 4-14 1 Reverse gear shaft assembly

When refitting, clutch shall be installed by

2 Countershaft assembly 38

BS428 Transmission Service Manual rotating. 2.

Put the assembled input shaft assembly to the mounting position in the transmission body. NOTE:

Make sure all sets of gears are correctly engaged.

Fig. 4-15 1 Input shaft assembly 3.

Install big end cap to the transmission body, and fasten the bolts connecting end cover and transmission body. About 41.5kg. NOTE:

Check and replace with new gasket.

Fig. 4-16 1 Big end cap 4.

Install external oil seal sleeves to each cover.

Fig. 4-17 1 External oil seal sleeve

39

BS428 Transmission Service Manual 5.

Install three sets of oil inlet end covers, and fasten the bolts connecting end cover and transmission body. NOTE:

● Check and replace with new gasket.

Fig. 4-18 1 Input shaft end cover 2 Reverse shaft end cover 3 Countershaft end cover ● Three oil inlet end covers have the same appearance but different inside oil passages. The oil passage of 1st and reverse gears are identical but different from that of neutral gear.

Fig. 4-19 1 1st/reverse gear end cover 2 Neutral gear end cover

4.2.2 Refitting of input flange and rear end cover 1.

Install oil seal into input shaft oil seal seat, install the bearing of input shaft in place by tapping, and measure and adjust the axial clearance of input shaft.

Fig. 4-20

Adjusting method: Use depthometer to measure the depth H from bearing (cone and cup) to the surface of the transmission body as well as the height h of oil seal seat step; select and add adjusting shim

40

BS428 Transmission Service Manual (δ=0.1mm) to ensure H-h-δ=0.1~0.15mm. 2.

Assemble input flange as well as washer, round nut and washer in turn and fasten round nuts using special tools.

Fig. 4-21 1 Round nut washer 2 Washer 3 Round nut

4.2.3 Assembly of countershaft and reverse gear shaft rear end cover 1.

Install bearing mounting paper washer, bearing cup and adjusting ring to the rear ends of reverse gear shaft and countershaft. Install the rear end covers of reverse hear shaft and countershaft and fasten them with bolts. Tap adjusting ring in place through the hole on the rear end cover.

Fig. 4-22 1 Adjusting screw 2 Adjusting ring 2.

Adjust the clearance of taper roller bearing supporting at both ends of the shaft through rotating the screw in the center of rear end cover. Install stop pad to fasten the adjusting screw. Adjusting methods:

Turn the adjusting screw to the limit and then return by about 15°(the screw pitch is 1mm and Fig. 4-23 1 Stop pad

the clearance required shall be 0.25~0.5mm).

41

BS428 Transmission Service Manual 3.

Input flange shall be rotated freely.

4.2.4 Assembly of output shaft 1.

Assemble bearing, gear, high/low gear sliding sleeve, spacer ring and thrust ring of the output shaft, and put them into transmission body. NOTE:

Low-speed gear can be put into transmission body Fig. 4-24 1 Output shaft assembly 2 Low-speed gear

from its bottom hole.

2.

Tighten the bolts connecting output rear end cover and transmission body and install 2 oil seals and dust covers.

3.

Install O-ring, pressure plate and fixing bolts that used to fix rear output flange, and fit lock plate.

Fig. 4-25 1 Bolt 2 Output rear end cover 3 Pressure plate 4 Bolt

4.2.5 Assembly of high/low gearshift fork mechanism 1.

Insert fork shaft, install fork, put fork shaft in the neutral position, set sliding sleeve to the spline tooth in the middle of output shaft, align fork shaft with the thread hole on the fork, then fasten

Fig. 4-26 1 Iron wire 2 Fixing bolt

screws and tighten with iron wire. NOTE: The high/low speed lever includes high, neutral

42

BS428 Transmission Service Manual and low gears, and the travel between two adjacent positions is 15mm. 2.

Install spring and steel ball, fasten screw plug and washer and install gearshift shaft oil seal.

Fig. 4-27 1 High/low gearshift fork 2 Screw plug 3 Steel ball 4 Spring 5 Oil seal

4.2.6 Assembly of oil sump 1.

Install gasket and fasten the bolts connecting oil sump and transmission body. NOTE:

● Check and replace gasket. ● The bolts shall be fastened diagonally in several steps. Fig. 4-28 1 Bolt

4.2.7 Assembly of transmission control valve 1.

Install upper paper washer, bottom plate and lower paper washer to transmission control valve.

2.

Erect transmission body and install transmission control valve to the transmission body.

Fig. 4-29 1 Bolt

NOTE: The bolts shall be fastened diagonally in several 43

BS428 Transmission Service Manual steps.

4.2.8 Assembly of breather and cover plate 1.

Install cover plate and paper washer, fasten the bolts on them and screw on the breather. NOTE:

The bolts shall be fastened diagonally in several Fig. 4-30 1 Cover plate 2 Breather

steps.

4.2.9

Assembly

of

parking

brake

assembly 1.

Install oil seal cover to transmission body.

2.

Install O-ring and pressure plate.

Fig. 4-31 1 Oil seal cover 2 Oil seal 3 Output shaft flange 4 Dust cover 5 Brake caliper disc

Fig. 4-32 1 Pressure plate 2 O-ring 44

BS428 Transmission Service Manual 3.

Screw up the fixing bolts on the output flange and assemble upper lock plate.

Fig. 4-33 1 Lock plate 2 Bolt 4.

Install parking brake and fasten connecting bolts.

Fig. 4-34

4.2.10 Assembly of oil filler pipe and filter 1.

Install filter with O-ring and fix them to transmission body.

Fig. 4-35 1 Filter 2 Oil filler pipe

2.

Install oil filler pipe and O-ring, and fasten connecting bolts.

45

BS428 Transmission Service Manual

5 Service Tools for Transmission Table 5-1 Special tools

Tool name

Location to be used

Remarks If

not

available,

a

Transmission mounting To support and tilt disassembly and assembly bracket

transmission platform can be set up.

Hoisting tools

End cover

M10

Round nut on the Socket input shaft Disassembly

and Three sets of clutch

assembly tool of clutch springs spring Spec: 0.02/0~200 Depth meter

Input shaft

Transmission pressure Pressure

joint

of 6410006223

joint

relief valve Use

with

pressure

joint

and

pressure

Pressure testing hose

4030000368 gauge.

Pressure gauge with a 6430000943 gauge of 25 bar

46

BS428 Transmission Service Manual

6 Common Fault Diagnosis and Troubleshooting Table 6-1 Symptoms

Probable causes

Solution

Low oil level, and empty pump

Check if the oil level is below oil dipstick and add oil

Oil suction filter element falls Check, wash and replace after off or is blocked up

removal

The inner layer of oil suction Check pipe is peeling off

removal

Air enters oil suction pipe

Check

and

replace

after

Relief valve is adjusted to a too Check, adjust and replace valve low pressure Pump abrasion and oil leakage

Replace pump

1. Weak traveling and gear The oil drain pipe of torque Check, wash and replace shift seizure

converter is blocked up The

opening

pressure

of Raise the opening pressure

overflow valve is too low Transmission clutch slipping

Check

transmission

after

removal Piston oil seal ring has abrasion Replace or damage Oil passage from relief valve to Check pipeline pilot valve is blocked up Transmission shaft end ring or Replace seal ring and sleeve sleeve shows abrasion 2. High oil temperature

Low oil level, and empty pump

47

Check oil level and add oil

BS428 Transmission Service Manual Symptoms

Probable causes

Solution

Oil suction filter element falls Check, wash and replace after off or is blocked up

removal

The inner layer of oil suction Check

and

pipe is peeling off

removal

Air enters oil suction pipe

Check

Pump abrasion and oil leakage

Replace pump

replace

after

Low transmission pressure and Raise pressure or find out clutch slipping

causes

Torque converter has large Check torque converter after inside leakage

removal

Oil temperature gauge and Replace sensing plug are broken Low oil level, and empty pump

Check oil level and add oil

Oil suction filter element falls Check, wash and replace off or is blocked up Air enters oil suction pipe or its Check and replace inner layer is peeling Transmission

shaft ring or Replace seal ring and sleeve

sleeve shows abrasion 3. Low oil pressure

Piston oil seal ring has abrasion Replace or damage The spring of relief valve is Check and replace valve broken Pump abrasion and oil leakage

Replace pump

Pressure valve is adjusted to a Adjust again too low pressure Oil passage from relief valve to Check pipeline 48

BS428 Transmission Service Manual Symptoms

Probable causes

Solution

pilot valve is blocked up Propeller shaft is installed in a Follow the direction of arrow wrong direction Vortex appears when opening Replace relief valve 4. Abnormal sound relief valve Internal parts are damaged or Check after removal gears have poor accuracy The positioning steel ball of Check and replace fork is abraded flat causing the ball unable to work normally Steel

ball

shows

serious Check and replace

abrasion 5. High/low gear is out of Spring is damaged

Check and replace

mesh The depth of positioning hole Check and replace for locking screw is insufficient causing the fork cannot be locked by screw securely Locking screw is sliding, etc.

Check and replace

Oil inlet end cover is installed Exchange 6. Only one gear is normal in a wrong way and

others

have

low The oil seal ring or piston ring Check and replace

pressure of other two gears are damaged 7.

Only

one

gear

is The clutch of one gear is burnt Check and repair

available, and the vehicle out and friction lining is unable can run even in the neutral to separate gear

49

BS428 Transmission Service Manual

50