General - Yale 524150797 Maintenance Manual

0630 YRM 1503
The master drive unit (MDU) includes the drive motor,
brake assembly, drive unit, and drive tire and wheel
assembly.
The drive motor is vertically mounted on top of the
MDU. In some instances, it may be necessary to
remove the drive motor to work on the MDU. In other
cases, the drive motor may remain attached to the
MDU while repairs are made. The complete MDU,
including the motor, may also be removed if
necessary. Determine the extent of disassembly
required before proceeding with any repairs.
NOTE: The drive unit bearings are lubricated by the
drive unit gear oil and do not require packing with
grease.
CAUTION
Some of the hardware used on the MDU and
traction motor is metric. Use the correct tools to
avoid damage.

General

The MDU is vertically installed in the truck and allows
an effective utilization of space. The compact, one-
piece housing is made of high-duty nodular iron; thus
having a high rigidity and optimum guiding precision.
This allows a fully integrated bearing of the helical
spur gear stage with a very high running smoothness;
i.e., no drive pinion on the motor shaft of the electric
motor.
The MDU consists of two ratio steps. Gear ratio 1 is
designed as helical spur gear stage and permanently
integrated in the housing. Gear ratio 2 is designed as
Gleason bevel gearing of the hypoid type with offset
bevel pinion shaft.
NOTE: There are no serviceable parts within the
drive unit. If repair of the master drive unit is required,
the entire assembly must be replaced.
General
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