ADVANCED TECHNICIANS COURSE TRANSMISSION

ADVANCED TECHNICIANS COURSE TRANSMISSION

1. ADVANCED
TECHNICIAN'S COURSE
4. TRANSMISSION
OVERSEAS SERVICE DEPARTMENT
HINO MOTORS, LTD

2. 1. Structure and Function
1) Transmission unit
SHIFTER SLEEVE
FLANGE
COUPLING
5th GEAR
INPUT
SHAFT
OUTPUT SHAFT
1st GEAR
2nd GEAR
REVERSE GEAR
O-RING
SPEEDO METER
DRIVE PINION
LOCK BALL
COUNTER SHAFT
OIL SEAL
OIL SEAL
COUNTER SHFT
DRIVE GEAR
SIFT & SELECT SHAFT LEVER

3. 2). Transmission gear shifting mechanism
(1) < Borg-Wagner type > Key type
Nowadays, this is the most widely used type because of
its goodoperatingcharacteristics and superiordurability.
GEAR
SLEEVE
SYNCHRONIZER RING
SYNCHRO CONE
GEAR
HUB

4. (2) < Pin-cage type > Pin type
A relatively large synchronous capacitycan be obtained because
the friction face diameter can be made largewithout restricting the
synchronous-breaking gear spline diameter.
SYNCHRO CONE
SYNCHRO RING SLEEVE SYNCHRONIZER PIN
HUB

5. This is a synchronous mechanism that has two or three times the
synchronous capacityof a conventional type by having two or three
synchro rings and synchronous-breaking gear taper cones.
(3) < Multicone type > Double synchro cone
SLEEVE
INNER CON
SINGLE CONE SYNCHRO DOUBLE CONE SYNCHRO
PIN
SYNCRONIZER RING
BUSH
SYNCHRO CONE
DOUBLE CONE
GEAR DOGSYNCRONIZER RING

6. 2. Troubleshooting
1 Transmission gear slipout
1) Trouble phenomena
The change lever returns to the neutral position while the vehicle is
traveling, even though it has not been shifted.

7. 2) Trouble Causes Chart
Use conditionsGear-related causes
Shift fork or sleeve groove wear
Shift shaft groove or lock ball wear
or deformation
Faulty lock ball spring tension or
broken spring
Shift head wear
Inversion lever wear
Excessive gear thrust play
Excessive gear radial play
Excessive hub and sleeve spline play
Gear dog or sleeve spline wear
Output shaft bearing wear
Control system play
Insufficient shift stroke
Stick cross shaft joint
Sudden acceleration on rough road
Instead shifting operation
Gear slipout
Transmission controlShift mechanism

8. 3) Conditions that produce slipout
(1) The engine brake on the downhill
During sudden acceleration
The load changes rapidly
A helical gearis adopted for the Hino transmission,
so a thrust force is produced when the load changes.

9. (2)When traveling on a rough road or at other times when
vibration is applied to the vehicle.
When the vehicle is vibrating, the transmission and
transmission control do not move in unison.

10. (3) Malfunction of gear anti-slip out device
Cross shaft

11. Shift shaft groove and ball
These parts determine the shift shaft position and
regulate its movement, using the force of a spring.
SPRING
BALL
SHIFT SHAFT

12. Sleeve steps
Hub, sleeve, and main gear steps for regulation of
sleeve movement
0.5
0.3
SLEEVE
HUB
MAIN SHAFT GEAR
The gear anti-slipout device and shifting force have a reciprocal
relationship: When the operating force is light, the gear can slip
out easily; when the gear cannot slip out easily, the operating
force is heavy.

13. (1) Transmission control
Insufficient shift stroke
4) Trouble causes
"L1 "
"L2 "
"L1 "
INSTRUMENT
CLUSTER
SHIFT
LEVER
KNOB
CENTER
STEERING
WHEEL
CENTER
Faulty change lever neutral positiondue to bent
or improperly adjusted transmission control rod.

14. (2) Shift mechanism
Shift shaft part
•Broken or slack spring
•Worn groove or ball
SPRING
BALL
SHIFT SHAFT

15. Shift head part
Large shifter fork and sleeve play
When the shift head is deformed due to wear or damage,
the change lever play becomes large; in extreme cases,
only the change lever slips out of position, while the gear
remains engaged.
Fork and sleeve groove wear

16. (3) Gear-related causes
Large gear thrust play
•Gear edge face wear
•Snap ring wear
•Inaccurate selection of snap ring thickness during overhaul
Large gear radial play
•Gear inner diameter and output shaft wear
•Needle bearing and bush wear
Large hub and sleeve play
Spline wear
Large output shaft play
Output shaft bearing wear

17. Gear slipout
Slipout due to vibration from
rough road
Slipout due to sudden acceleration
(excessive power line front/rear
movement)
Slipout during forward travel
Slipout during acceleration or
deceleration
Slipout due to sudden
acceleration
Faulty T/M unit
Faulty shift operation
Dog addendum and sleeve inner
diameter interference
Faulty control adjustment
Link system
interference
Sticky cross shaft join
Faulty control adjustment
Excessive control system play
Shift mechanism wear
Shift mechanism and link
interference
Excessive 2-stage
shifting force
Faulty power shift operation
Excessive gear radial play
Excessive gear thrust play
Excessive hub sleeve play
Dog sleeve taper wear
Hub stepped wear
Main shaft vibration
MECHANISM OF T/M GEAR SLIPOUT
Faulty T/M control

18. 2 Heavy Change Lever Operation
1) Outline
Check the oil
Control system
Synchromesh mechanism
Circumstances

19. 2) Trouble Causes Chart
Gear oilTransmission unit
Control link hesitation
Faulty sliding of shift lever shaft
Faulty sliding of shut shaft
Faulty interlock device
Faulty control link adjustment
Synchronizer ring cone sliding part wear
Faulty synchronizer ring and cone contact
Worn or damaged shifter sleeve or
synchronizer ring cone chamfer
Worn or damaged main shaft and
input shaft bearings
Output shaft bearing wear
Faulty clutching
Excessive quantity of gear oil
Excessive viscosity
Heavy change lever operation
ClutchTransmission control

20. 3) Trouble Causes
(1) Clutch
[1] Faulty clutching
Whenclutchingisfaulty,theshift
operationisextremelyheavyand
itisdifficulttoengageordisengage
agear,regardlessofgearpositionor
whetherthevehicleisrunningor
taking off.

21. (2) Gear oil
[1] Excessive viscosity
Whenthegearoilviscosityistoohigh,
thegearoilstirringresistanceofeach
ofthecountershaftgearsincreases,
andthesynchronizingactionofthe
synchromeshmechanismrequires
alargeforce,soitisdifficulttoengage
gears.

22. (3) Transmission Control
[1] Control link hesitation
[2] Faulty control link adjustment
[3] Faulty shift lever shaft operation
[4] Faulty shift shaft operation
[5] Faulty interlock mechanism
FAULTY SLIDING OF INTERLOCK PIN
FAULTYSLIDING OF SHIFT SHAFT

23. (4) Transmission Unit
[1] Synchronizer ring and gear cone sliding part wear
[2] Faulty contact of synchronizer ring and cone
[3] Sleeve spline chamfer and synchronizer ring chamfer wear
SLEEVE
SYNCRONIZER
RING
CHAMFER PART WEAR
SYNCRONIZER
PIN
SLEEVE
WEAR PART
SYNCRONIZER RING
GEAR DOG PART
SLIDING PART

24. [4] Faulty relative position of sleeve chamfer and synchronizer chamfer
[5] Worm main shaft and input shaft bearing
GEAR DOG PART
SYNCRONIZER
RING
SYNCRONIZER SLEEVE
SYNCRONIZER HUB
CHAMFER PART
SHIFT DIRECTION

25. MECHANISM OF FAULTY T/M
GEAR ENGAGEMENT
Faulty gear engagement
Heavy gear engagement/
disengagement
Gear locked and shifting
is impossible
Gear noise is produced
Excessive 2-stage
shifting force
Faulty T/M control
Insufficient unit stroke
Faulty clutching
Faulty control adjustment
Link system interference
Faulty interlock operation
Faulty control adjustment and rubbing
Shift mechanism or link interference
Shift mechanism wear
Faulty ring set position
Excessive oil deterioration (sludge)
Faulty taper face contact
Faulty taper face thread or groove
Taper face wear or seizing
Friction material peeling or damage
Dog addendum or sleeve addendum
wear
Faulty dog teeth or sleeve teeth
precision
Insufficient
synchromesh force
Insufficient rear gap
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)