4-9. GENERAL MAINTENANCE PROCEDURES - Continued
4-9 3 General Inspection Instructions - Continued
Inspect shaft splines for wear. This will include pitting, peening or fatigue cracks. Perform magnetic particle
inspection if needed.
Inspect all wiring for chaffed or burned insulation. Check all terminals for tightness. Check all lamps for failure.
Check for burns, or broken fittings or components.
The following steps should be used to make a general visual inspection of all gears. Specific tests for particular
gears, outlined in the text, should also be carried out if any gear looks faulty, perform a surface temper and/or
magnetic particle inspection.
Normal Wear. Loss of metal from surface of teeth. Wear must not prevent gears from meshing or
Initial Pitting. This may occur when gears are first put into service it may continue until high spots have
been reduced it will not affect contact surfaces. This pitting is not necessarily serious.
Destructive Pitting. This pitting occurs after initial pitting, often at an increasing rate. This type will destroy
the contact area and reduce the load capacity of the gear. Rapid destruction will occur with use.
Abrasive Wear. This damage is caused by fine particles carried in the lubricant or embedded in gear
tooth. This material may come from:
Bearing or gear tooth material
Abrasives not removed during assembly
Sand or scale from castings
Impurities from oil or the environment
Scoring. Slight scoring, galling or other surface damage is seen as tears or scratches in the direction of
sliding. It starts in areas of highest stress and speed. This is usually at tip of teeth.
Burning. Burning is seen as discoloration, and causes loss of hardness of the metal. Burning is caused by
any of the following:
Lack of Backlash
Too Little Lubrication