
1400 SRM 618 Drive Unit Assembly Repair
General
This section has the description and repair proce-
dures for the differential, speed reducer, axle, and
the wheel bearings for the axle housing.
WARNING
The lift truck must be put on blocks for some
types of maintenance and repair. The removal
of the following assemblies will cause large
changes in the center of gravity: mast, drive
unit, battery, and the counterweight. When
the lift truck is put on blocks, put additional
blocks in the following positions to maintain
stability:
a. Before removing the mast and drive unit,
put blocks under the counterweight so that
the lift truck cannot tip backward.
b. Before removing the battery and counter-
weight, put blocks under the mast assembly
so that the lift truck cannot tip forward.
The surface must be solid, even, and level when
the lift truck is put on blocks. Make sure that
anyblocksusedtosupportthelifttruckare
solid, one-piece units.
Observe the previous warning before doing any re-
pairs.
Description
The drive unit is fastened to the frame of the lift
truck with trunnions and bolts. The outer ends of
theaxlehousingsarethespindlesforthewheelbear-
ings. The cups for the tapered roller bearings for the
wheel bearings are pressed into the hubs. The nut
on the end of the spindle holds the hub and adjusts
the preload on the wheel bearings. The axle shafts
are fastened to the hubs by capscrews and the studs
and nuts that fasten the wheels.
The drive axles have an oil seal between the inner
and outer bearings of the hub and a second oil seal
near the inner bearing.
The speed reducer and differential are parts of the
same assembly. See Figure 7. One speed reducer
gear is installed on the shaft of the traction motor.
A second speed reducer gear is fastened to the pinion
shaft for the differential.
Drive Unit Assembly Repair
REMOVE COMPLETE DRIVE UNIT
ASSEMBLY AS A UNIT
WARNING
The lift truck must be put on blocks for some
types of maintenance and repair. The removal
of the following assemblies will cause large
changes in the center of gravity: mast, drive
unit, battery, and the counterweight. When
the lift truck is put on blocks, put additional
blocks in the following positions to maintain
stability:
a. Before removing the mast and drive unit,
put blocks under the counterweight so that
the lift truck cannot tip backward.
b. Before removing the battery and counter-
weight, put blocks under the mast assembly
so that the lift truck cannot tip forward.
The surface must be solid, even, and level when
the lift truck is put on blocks. Make sure that
anyblocksusedtosupportthelifttruckare
solid, one-piece units.
NOTE: The drive unit assembly can be removed with
the traction motor as one unit. However, many ser-
vice technicians remove the traction motor before the
drive unit is removed. Motor removal reduces the to-
tal weight of the drive unit assembly. If another lift
truck is not available, remove the motor first. See
Traction Motor, Remove to remove the traction mo-
tor.
Use the following procedure to remove the complete
drive unit as one assembly using another lift truck:
1. Operate the hydraulic pump and tilt the mast
fully backward. Put blocks under the bottom of
the outer channel of the mast. Tilt the mast for-
ward until the wheels just touch the floor. Put
1