TM 1-1520-238-23
6-98
Change 4
6.17.
ENGINE NOSE GEARBOX INSPECTION – continued
e. Check gearbox and lube oil pump housings for cracks. None allowed.
(1) Clean suspected areas. Use brush (item 34, App F) and methyl ethyl ketone (item 124, App F).
(2) Fluorescent penetrant inspect for fractures and/or cracks (TM 55-1500-335-23). Use fluorescent
inspection kit.
f. Check gearbox cooling fins for broken or damaged cooling fins.
(1) 10 degree maximum allowable bend in fins.
(2) Damage to fins less than 0.250 INCH or less deep, by blending. Use depth gage.
(3) Check for broken or cracked fins. None allowed.
g. Check gearbox electrical components (low oil pressure switch, pressure transducer, temperature
probe, and chip detector) for cracked, broken, or burned insulation.
(1) Check for secure splices to gearbox harness.
h. Check wiring for cracked, burned, or worn insulation.
i. Check wire bundles for chafing, loose mounting, and broken or missing wire ties.
j. Check gearbox input fan for cracks, broken blades, or deformation. None allowed.
(1) Remove fan shroud for access.
k. Check diffuser for cracks or deformation. None allowed.
l. Check gearbox for serviceability.
(1) Check for fractures and/or cracks. None allowed. Use fluorescent inspection kit.
(2) Check for nicks, gouges, burrs, and corrosion.
(a) Repair damaged areas 0.060 INCH or less deep, by blending. Use depth gage.
(b) Blended areas shall be 0.50 INCH long maximum and at least 1 INCH apart.
(c) Total repaired area shall be no more than 10 percent of housing surface area. 10 percent of total fix
area may be missing.
(3) Check studs for fractures or cracks. None allowed.
(4) Check studs for crossed, flattened, or stripped threads. None allowed.
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