TRUCK SERVICE MANUAL
HT 700D SERIES TRANSMISSIONS
4-4. CAREFUL HANDULING
(2) If the bearings a r e particularly dirty or filled with
During all rebuild procedures, parts and
hardened grease, soak them in the spirits before
subassemblies must be handled carefully to prevent
trying to clean them.
nicking, scratching and denting. Parts which fit together
closely and have proper operating clearance can bind if
(3) Before inspection, oil the bearings with the same
damaged. Parts which depend upon smooth surfaces for
type of oil that will be used in the transmission.
sealing may leak if scratched. This is very important
concerning parts of the control valve body assembly
(valves, when dry, must move freely by their own weight).
Such parts should be carefully handled and protected
Never dry bearings with compressed air. Do not spin
during removal, cleaning, inspection and installation as
bearings while they are not lubricated.
well as being kept clean while in containers awaiting
d. Keeping Bearings Clean. Since the presence
of dirt or grit in ball bearings is usually responsible for
4-5. CLEANING, INSPECTION
bearing failures, it is important to keep bearings clean
during removal and installation. Observance of the
a. Dirt Causes Malfunction. All parts must be
following rules will do much to insure maximum bearing
clean to permit effective inspection. At assembly, it is
very important that no dirt or foreign material be allowed
to enter the transmission. Even minute part i c 1 e s can
(1) Do not remove the wrapper from new bearings
cause the malfunction of close-fit parts, such as valves.
until ready to install them.
b. Cleaning Parts
(2) Do not remove the grease in which new bearings
(1) All the metallic parts of the transmission except
bearings and friction-faced clutch plates should
(3) Do not lay bearings on a dirty bench; place them
be cleaned thoroughly with volatile mineral spirits
on clean, lint-free paper.
or by the steam cleaning method. Do not use
caustic soda solution for steam cleaning. Use
(4) If assembly is not to be completed at once, wrap
only mineral spirits to clean friction-faced clutch
or cover the exposed bearings with clean paper
or lint-free cloth to keep out dust.
(2) Parts should be dried with compressed air.
e. Inspecting Cast Parts, Machined Surfaces.
immediately after drying.
(1) Inspect bores for wear, scratches, grooves and
dirt. Remove scratches and burs with crocus
(3) Clean oil passages by working a piece of soft
cloth. Remove foreign matter. Replace parts
wire back and forth through the passages and
that are deeply scratched or grooved.
flushing with mineral spirits. Dry the passages
with compressed air.
(2) Inspect all oil passages for obstructions. If an
obstruction is found, remove it with compressed
(4) Examine parts, especially oil passages, after
air, or by working a soft wire back and forth
cleaning, to make certain they are entirely clean.
through the passage and flushing it out with
Reclean them if necessary.
c. Cleaning Bearings
(3) Inspect mounting faces
for nicks, burs,
(1) Bearings that have been in service should be
scratches, and foreign
thoroughly washed in volatile mineral spirits.