Page 4702 of 6020
7B1-96 MANUAL TRANSMISSION
• Use the bearing installer 5-8840-2194-0 to install
the ring.
RTW 57BSH000101
Legend
(1) Ring
(2) Outer Race and Roller Assembly
(3) Inner Race
3. Install the bearing snap ring to the counter gear
shaft.
4.
Apply engine oil to the needle bearing and the 2nd
gear thrust surfaces.
Install the needle bearing and the 2nd gear to the
mainshaft.
The 2nd gear dog teeth must be facing the
transmission rear side.
226RS046
5.
Assemble the 2nd inside ring, 2nd outside ring, and
the 2nd block ring.
•
Apply engine oil to the synchronizer ring friction
surfaces.
226RS047
Legend
(1) Block Ring
(2) Outside Ring
(3) Inside Ring
(4) 2nd Gear
(5) Needle Bearing
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ISUZU KB P190 2007
Page 4704 of 6020
7B1-98 MANUAL TRANSMISSION
226RS031
9. Install the needle bearing, 1st block ring, 1st outside
ring, 1st inside ring, and 1st gear.
•
Apply engine oil to the needle bearing, 1st gear
thrust surfaces and synchronizer ring friction
surfaces.
• The 1st gear dog teeth must be facing the
transmission front side.
226RS053
Legend
(1) 1st Gear
(2) Needle Bearing
(3) Inside Ring
(4) Outside Ring
(5) Block Ring
10. Install the 1st gear thrust bearing and the race to the
main shaft.
The thrust bearing side must be facing the
transmission front side.
226RS054
11. Apply engine oil to the mainshaft ball bearing and the mainshaft.
Install the ball bearing and needle bearing collar to
the mainshaft.
The ball bearing snap ring groove must be facing
the transmission rear side.
Use a bench press and installer 9-8522-1165-0 to
slowly force the collar into place.
226RS055
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ISUZU KB P190 2007
Page 4705 of 6020

MANUAL TRANSMISSION 7B1-99
12. Apply engine oil to the needle bearing and the 3rd
gear thrust surfaces.
Install the needle bearing and the 3rd gear to the
mainshaft.
The 3rd gear dog teeth must be facing the
transmission front side.
226RS056
13. Install the 3rd block ring.
14. Check and install the 3rd-4th synchronizer assembl
y
by using the following steps:
1. Check that the inserts (3) fit snugly into the clutch hub insert grooves.
2. Check that the insert springs (4) are fitted to the inserts as shown in the illustration.
3. Check that the clutch hub (5) and the sleeve (6) slide smoothly.
4. Install the synchronizer assembly to the mainshaft.
The clutch hub face with the heavy boss must be facing the 3rd gear side.
226RS049
226RW 221
15. Select and install mainshaft snap ring using the
following instructions:
Select the snap ring which will provide the minimum
clearance between the 3rd-4th clutch hub and the
snap ring.
226RS058
There are three snap ring sizes available.
The snap rings are color-coded to indicate thei
r
thickness, as shown in the figure.
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ISUZU KB P190 2007
Page 4707 of 6020
MANUAL TRANSMISSION 7B1-101
Main Data and Specifications
General Specifications
MUA5G MUA5H MUA5S
Transmission type Fully synchronized forward and reverse gears
Control method Remote control with the gear shift lever on the floor.
Gear ratio: Transmission 1st 4.008 4.008 4.357
2nd 2.301 2.301 2.502
3rd 1.427 1.427 1.501
4th 1.000 1.000 1.000
5th 0.828 0.744 0.809
Rev. 3.651 3.651 3.970
Transmission oil capacity 2.95 lit. (3.12 US qt)
Type of lubricant Engine oil: Refer to the chart in "SECTION 0"
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ISUZU KB P190 2007
Page 4711 of 6020
MANUAL TRANSMISSION 7B1-105
TROUBLESHOOTING
1. ABNORMAL NOISE
1) NOISY IN NEUTRAL
Checkpoint Trouble Cause Countermeasure
Replenish or replace the gear
oilInsufficient or improper gear
oil
NG
Mainshaft splines
Synchronizer clutch hub
splinesReplace the main shaft and
the synchronizer clutch hub
Replace the gear(s)
Replace the flywheel pilot
W orn splines
W orn or scuffed gear tooth
contact surfaces
Flywheel pilot bearingW orn flywheel pilot bearing
Bearings (Mainshaft,
countershaft, and transfer
shaft)
Gears (Mainshaft,
countershaft, reverse idler
gear and transfer gears)
Replace the bearing(s)W orn or broken bearing(s)
OK NG
NG
NG
NG
OK
OK
OK
Gear oil
TransmissionRealign the transmissionTransmission misalignment
OK
NG
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ISUZU KB P190 2007
Page 4712 of 6020
7B1-106 MANUAL TRANSMISSION
2) NOISY OPERATION
Checkpoint Trouble Cause Countermeasure
Replenish or replace the gear
oilInsufficient or improper engine
oil
NG
Replace the gear(s)
Replace the gear(s)
Replace the bearing(s)
Gears (Gear whining)Lack of backlash between
meshing gears
Free running gears seizing on
the thrust face or the inner
face
Bearings (Hissing, thumping
or bumping)W orn or broken bearing(s)
Gears (Squealing at high
speeds)
Replace the gear(s)Gears (Growling, humming, or
grinding)W orn, chipped, or cracked
gear(s)
NG
NG
NG
NG
OK
OK
OK
OK
Gear oil (Metallic rattling)
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ISUZU KB P190 2007
Page 4713 of 6020
MANUAL TRANSMISSION 7B1-107
2. HARD SHIFTING
Checkpoint Trouble Cause Countermeasure
Change lever play
Clutch pedal free play
Repair or replace the
applicable parts and regrease
Readjust the clutch pedal free
play
W orn change lever sliding
portions
Improper clutch pedal free
play
Change lever operationRepair or regrease the change
lever assembly
Replenish or replace the
engine oil
Hard operating change lever
caused insufficient grease
Insufficient or improper gear
oil
OK
OK NG
NG
NG
NG
OK
OKGear oil
Continued on the next page
Shift rod and quadrant box
sliding faces, and other partsReplace the shidt rod and/or
the quadrant boxW orn shift rod and/or sliding
faces
Repair or replace the sleeveSleeve movement failure
NG
NG
OKShift block sleeve movement
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ISUZU KB P190 2007
Page 4717 of 6020
MANUAL TRANSMISSION 7B1-111
4. OIL LEAKAGE
Checkpoint Trouble Cause Countermeasure
Gear oilReplace the gear oilImproper gear oil
Drain plug and/or filler plugTighten the plug(s) and
replenish the oil
Drain the oil to the correct
level
Loose plug(s)
Oil level too high
OK NG
NG
NG
OK
OKOil level
Rear cover oil seal
Air breather
Replace the oil seal
Install the air breather
Replace the air breather
W orn or scratched oil seal
Air breather not installed
Air breather clogged
Front cover oil sealReplace the oil seal
Replace the gasket(s)
W orn or scratched oil seal
Defective or improperly
installed gasket(s)
OK NG
NG
NG
NG
OK
OKGaskets
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ISUZU KB P190 2007