MAINTENANCE
SECTION II
General Precautions for Disassembly
IMPORTANT
Read this section before starting the detailed
disassembly procedure.
Follow each procedure closely in each section,
making use of both the text and the pictures.
Rebuild Facilities
A suitable holding fixture or overhaul stand is desirable,
but not necessary, to rebuild this unit. The flat bottom of
the transmission case provides a suitable working
platform when the unit is placed on a sturdy shop table.
For easier working conditions, table height should be 28-
30 inches A light chain hoist should be used to handle
the mainshaft and countershafts during removal and
reassembly procedures.
Cleanliness
Transmissions should be steam cleaned prior to
disassembly. Seal all openings before steam cleaning.
This will prevent dirt and water entry, which can damage
serviceable parts.
Dirt is abrasive and will cause premature wear of
bearings and other parts. Therefore, we suggest having
a small wash tank nearby so parts can be cleaned prior
to reassembly.
Bearings
When a transmission is removed at relatively low
mileage, the bearings should be removed with pullers
designed for this purpose. Wrap the bearings to keep
out dirt. Clean, inspect and lubricate all bearings just
prior to reassembly. If mileage or transmission condition
warrants a complete overhaul, it is recommended that all
bearings be replaced.
End Yokes and Flanges
End yokes and flanges should be installed and removed
with the correct drivers and pullers-not with a hammer.
Hammering is not only destructive to the yoke or the
flange, but also can cause serious internal transmission
damage. For example, hammering destroys or mutilates
the pilot diameters, as well as warps or bends the flange.
Hammering on end yokes will close in the bearing bores
or misalign yoke lugs, resulting in early journal needle
bearing failures.
In most designs, when the yoke/flange locknuts are
tightened and secure, the internal bearings and gears
are in proper location. When the yoke/flange is driven on
the shaft, however, two conditions can exist.
(a)
If the bearing fit is tight on the shaft, usually the
bearings will brinell since they absorb the
pounding force of the hammer.
(b)
If the bearing fit is loose, the shaft will keep
moving inward until it is stopped by the internal
parts such as the pilot bearing thrust washers
and snap rings.
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