2. 1400 SRM 1223 Description
General
This section has the description and repair procedures for the differential, drive axle, traction motor, and the
wet disc brakes.
Description
The drive unit consists of following main components
(see Figure 1):
• The traction motor with hollow shaft.
• Mechanical differential assembly (located on left-
hand side of traction motor shaft).
• The gearbox with intermediate flange, containing
the wet disc brakes.
• Main housings, containing the pistons for the wet
disc brakes and the parking brake levers.
• Speed sensor and reluctor wheel (located on trac-
tion motor shaft, see Figure 8).
1. WHEEL HUB
2. GEARBOX (LH)
3. INTERMEDIATE FLANGE (LH)
4. MAIN HOUSING (LH)
5. PARKING BRAKE LEVER
6. TRACTION MOTOR
7. MAIN HOUSING (RH)
8. INTERMEDIATE FLANGE (RH)
9. GEARBOX (RH)
10. SPEED SENSOR
11. DIFFERENTIAL ASSEMBLY
Figure 1. Drive Unit
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3. Description 1400 SRM 1223
The drive unit assembly is fastened to the frame of
the lift truck by the frame mounts of the main hous-
ings. See Figure 2.
The mast is mounted on the J-hook mountings of the
main housings of the drive unit. See Figure 3.
The traction motor is mounted in between the two
main housings. The traction motor generates the
power to the differential assembly. See Figure 4.
1. FRAME MOUNTS
Figure 2. Drive Unit Frame Mounts
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5. Description 1400 SRM 1223
The differential then transfers the power through the
axle shaft to the input shafts located in the interme-
diate flange assemblies. The input shaft drive gears
transfer the power to the driven gears. The driven
gears then transfer the power to the sun pinion. See
Figure 5.
1. DRIVE GEAR
2. INTERMEDIATE FLANGE
3. INPUT SHAFT
4. AXLE SHAFT
5. DRIVEN GEAR
6. SUN PINION
Figure 5. Drive Gear, Driven Gear, and Sun
Pinion
The sun pinion then transfers the power to the plane-
tary gears and planetary carrier which then engages
the wheel hubs. See Figure 6.
1. PLANETARY CARRIER
2. PLANETARY GEARS
3. RING GEAR
4. WHEEL HUB
Figure 6. Planetary Gears
The wet brake discs are mounted on the interme-
diate flanges. The piston, which is located in the
main housing (one in each main housing), is acti-
vated when the brake pedal is applied. The piston
presses against the disc pusher which compresses
the brake friction discs and steel discs which causes
the braking. See Figure 7.
The parking brake levers press against the back of
the piston which forces the piston to press against the
disc pusher to compress the brakes friction discs and
steel discs to mechanically apply the parking brake.
The speed sensor is mounted on the main housing on
the right-hand side of the drive unit. The reluctor
wheel is mounted on the traction motor shaft on the
right-hand side of the traction motor. The speed sen-
sor is a hall effect sensor which reads the variation in
its magnetic field when a tooth of the reluctor wheel
passes the sensor. See Figure 8.
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6. 1400 SRM 1223 Wet Disc Brake Repair
1. INTERMEDIATE FLANGE
2. DISC PUSHER
3. BRAKE DISC PACK
Figure 7. Brake Disc Pack
1. SPEED SENSOR
2. RELUCTOR WHEEL
Figure 8. Speed Sensor and Reluctor Wheel
Wet Disc Brake Repair
WET DISC BRAKES
For replacement of the pistons and piston seals, refer
to the section Main Housing Repair.
Remove
STEP 1.
Remove the gearbox. Refer to the section Gearbox Replacement.
STEP 2.
Press down on the disc pusher device and remove the
retaining rings from the studs.
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7. Wet Disc Brake Repair 1400 SRM 1223
STEP 3.
Remove the disc pusher device from the studs.
1. DISC PUSHER DEVICE
2. STUDS
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8. 1400 SRM 1223 Wet Disc Brake Repair
STEP 4.
Remove the springs from the studs.
If necessary, remove the studs.
1. STUDS
2. SPRINGS
STEP 5.
Note the position of the notches on the steel discs for
correct positioning during assembly.
Remove one steel disc.
1. STEEL DISC
2. NOTCH
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9. Wet Disc Brake Repair 1400 SRM 1223
STEP 6.
Remove the one friction disc.
1. FRICTION DISC
STEP 7.
Remove four springs/spacers.
1. SPRINGS/SPACERS
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10. 1400 SRM 1223 Wet Disc Brake Repair
STEP 8.
Repeat STEP 5 through STEP 7 until the last steel disc is removed.
STEP 9.
Remove the aluminum reaction disc.
Inspect
1. Inspect the brake friction discs and brake steel
discs. The discs must be measured as a pack (6
steel discs and 5 friction discs) to determine if
the discs need replaced. Replace discs as a pack
when the thickness is less than 23 mm (0.91 in.).
A new disc pack will have a thickness of 23.95 to
24.45 mm (0.94 to 0.96 in.). When replacing the
disc pack, all springs must also be replaced.
2. Inspect the aluminum reaction disc. Replace the
aluminum reaction disc when the thickness is
equal or less than 4.5 mm (0.18 in.). A new alu-
minum reaction disc will have a thickness of 4.95
to 5.05 mm (0.195 to 0.199 in.).
Install
STEP 1.
If removed, install the four pins.
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11. Wet Disc Brake Repair 1400 SRM 1223
STEP 2.
If removed, apply Loctite® 242 to the studs and install
the studs. Tighten the studs to 2 N•m (17.7 lbf in).
STEP 3.
Install the aluminum reaction disc.
NOTE: The first and last disc installed must be a smooth steel disc.
STEP 4.
Align the notch of the steel disc as noted during dis-
assembly.
Install one steel disc.
1. NOTCH
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12. 1400 SRM 1223 Wet Disc Brake Repair
STEP 5.
Install one friction disc.
STEP 6.
Install four springs/spacers.
STEP 7.
Repeat STEP 4 through STEP 6 until six steel discs and five frictions discs have been installed.
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15. Gearbox Replacement 1400 SRM 1223
STEP 10.
Press down on the disc pusher device and install the
retaining rings into the seats on the studs.
STEP 11.
Install the gearbox. Refer to the section Gearbox Re-
placement.
Gearbox Replacement
REMOVE
Gearbox Removal
WARNING
When putting the lift truck on blocks, make
sure the surface is solid, even, and level. Any
blocks used to support the lift truck must be
solid, one-piece units.
1. Put blocks on each side (front and back) of the
steering tires to prevent movement of the lift
truck.
2. Raise the lift truck and put blocks under the
frame so that the drive wheels do not touch the
floor. Put blocks under the counterweight for
stability.
3. Remove the mast assembly as described in the
section Mast Repairs, 2, 3, and 4-Stage Masts
4000 SRM 1148.
4. Disconnect the battery connector.
5. Remove the wheel from the wheel hub of the
gearbox being replaced.
6. Remove the gearbox oil fill plug. See Figure 9.
7. Remove the gearbox magnetic drain plug to drain
the oil from the gearbox into a suitable container.
See Figure 9.
8. Remove the brake oil fill/breather plug from
main housing. See Figure 9.
9. Remove the brake oil drain plug to drain the oil
from the main housing into a suitable container.
See Figure 9.
10. Place a sling connected to an overhead lift around
the gearbox and wheel hub assembly and apply
light tension to the sling.
11. Remove the socket-head screws retaining the
gearbox to the main housing. Note the positions
of the short and long socket-head screws for
when the gearbox is installed. See Figure 10.
12. Remove the gearbox and wheel hub assembly.
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16. 1400 SRM 1223 Gearbox Replacement
1. BRAKE OIL FILL/BREATHER PLUG
2. GEARBOX OIL FILL PLUG
3. GEARBOX OIL DRAIN PLUG (MAGNETIC)
4. BRAKE OIL DRAIN PLUG
Figure 9. Oil Refill and Drain Plugs
1. M8 SOCKET-HEAD SCREWS, 3 EACH
2. M12 X 1.75 X 70 MM LONG SOCKET-HEAD
SCREWS, 11 EACH
3. M12 X 1.75 X 40 MM SHORT SOCKET-HEAD
SCREWS, 2 EACH
Figure 10. Gearbox Removal/Installation
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17. Gearbox Replacement 1400 SRM 1223
Intermediate Flange Removal
STEP 1.
Remove the brake discs and friction plates. Refer to the section Wet Disc Brake Repair.
STEP 2.
For the left-hand side gearbox only, remove the
spacer from the input shaft.
STEP 3.
Remove the socket-head screws used to retain the in-
termediate flange to the gearbox housing.
Insert a prybar into the pry slots between the inter-
mediate flange and the gearbox housing and pry up-
wards to break the seal between the flange and hous-
ing.
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18. 1400 SRM 1223 Gearbox Replacement
1. SOCKET-HEAD SCREWS
2. PRY SLOTS
STEP 4.
Remove the intermediate flange assembly from the
gearbox housing.
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20. Gearbox Replacement 1400 SRM 1223
DISASSEMBLE
The gearbox is to be replaced as an assembly and is
not disassembled.
Intermediate Flange
NOTE: If the inner ring for the needle bearing is being replaced, the needle bearing in the gearbox housing
must be replaced.
STEP 1.
Using an appropriate puller, remove the needle bear-
ing from the gearbox housing.
1. GEARBOX
2. NEEDLE BEARING
STEP 2.
Remove the snap ring retaining the input shaft into
the intermediate flange.
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21. 1400 SRM 1223 Gearbox Replacement
1. SNAP RING
2. INPUT SHAFT
STEP 3.
Using plastic or hard rubber hammer, tap the input
shaft, on the gear side, with drive gear and bearing
out of the intermediate flange.
1. INTERMEDIATE FLANGE
2. INPUT SHAFT ASSEMBLY
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22. Gearbox Replacement 1400 SRM 1223
STEP 4.
Remove the retaining ring from the input shaft.
STEP 5.
Place a cylinder on the press workbench as shown.
Cylinder dimensions:
• Inside diameter - 41 mm (1.61 in.)
• Outside diameter - 62 mm (2.44 in.)
• Height - minimum 130 mm (5.12 in.)
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23. 1400 SRM 1223 Gearbox Replacement
STEP 6.
Place the input shaft assembly with drive gear side
up on the cylinder.
Place a cylinder (solid shaft) on top of the input shaft
and use a press to press the input shaft out of the nee-
dle bearing inner ring, the drive gear, and the bear-
ing.
Cylinder dimensions:
• Diameter - maximum 18.5 mm (0.73 in.)
• Height - minimum 45 mm (1.77 in.)
1. CYLINDER
2. NEEDLE BEARING INNER RING
3. DRIVE GEAR
4. BEARING
5. CYLINDER
6. WORKBENCH
STEP 7.
Remove the square key from the input shaft.
1. NEEDLE BEARING INNER RING
2. DRIVE GEAR
3. BEARING
4. SQUARE KEY
5. INPUT SHAFT
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