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TM 9-2320-360-34-1
2-10. GENERAL INSPECTION INSTRUCTIONS
a.
Inspection. Inspection consists of checking for defects such as distortion, wear, cracks, and pitting. Clean all
parts before inspection.
b.
Sealing Surfaces. Inspect all surfaces in contact with gaskets, packings, or seals. Ensure there are no nicks,
burrs, or scratches. If any defect is found, replace or repair it as outlined in para 2-11.
c.
Bearings. Check bearings for rusted or pitted balls, races, or separators. Check balls and races for brinelling,
abrasion, and discoloration. Following are causes for bearing rejection:
(1)
Cuts or grooves parallel to ball or roller rotation.
(2)
Pits
(3)
Cracks.
d.
Drain Plugs. When removing drain plugs from transmission, engine, or hydraulic system components, inspect
sediment adhering to plug. A few fine particles are normal. A build-up of grit or fine metal particles may indicate part
failure. This inspection is effective in determining defective parts prior to internal inspection of parts.
e.
Gears. Gear inspection cannot be described in detail here. There are too many differences in size and shape of
gears. The following steps can be used to make a general visual inspection of all gears. Follow all steps listed within
repair instructions for final inspection.
(1)
Normal Wear. Loss of metal from the surface of gear teeth. Wear must not prevent gears from meshing or
performing properly.
(2)
Initial Pitting. This may occur when a pair of gears is first started in service. It may continue until most high
spots have been reduced, as long as contact surfaces are not affected. This pitting is not necessarily serious.
(3)
Destructive Pitting. This type of pitting occurs after initial pitting, often at an increasing rate. This will
destroy contact area and reduce the gear's ability to carry a load. Rapid destruction will occur with use.
(4)
Abrasive Wear. This damage is caused by the fine particles carried in the lubricant or imbedded in the gear
teeth. These particles may come from many sources:
metal detached from gear teeth or bearings, abrasives not
completely removed before assembly, sand or scale from castings, or other impurities in oil or air.
(5)
Scoring. Slight scoring, scuffing, galling, or other surface damage is identified by tears or scratches in the
direction of sliding. It starts in areas having the highest stress and speed. This is usually at the tip of the teeth.
(6)
Burning. Burning is indicated by discoloration and loss of hardness due to excessive temperature. This is
caused by too much friction resulting from overload, overspeed, lack of backlash, or faulty lubrication. If discoloring can
be wiped off with clean cloth, such discoloring usually can be traced to oil burn-stains, which are not serious.
(7)
Rolling. This damage occurs mainly on plastic gears. Rolling is when material is pushed out of shape
without breaking off. This is caused by heavy, even loads, sliding, or overheating.
(8)
Brinelling. This can be identified by tiny indentation or ridges on the shoulder or race of a bearing.
f.
Splines. Inspect shaft splines for wear, pitting, rolling, peening, and fatigue cracks.
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