AGB GEAR TRAIN TURNS UNEVENLY (BINDS) WHEN TURNED BY HAND AND THERE ARE METAL CHIPS IN THE OIL PUMP TO OIL COOLER FLUID FILTER.

TM 9-2835-255-34

3-2. TROUBLESHOOTING - CONTINUED

(6) ES-6. AGB GEAR TRAIN TURNS

a. ACCESSORY GEARBOX (AGB) AND

UNEVENLY (BINDS) WHEN TURNED BY

HIGH PRESSURE COMPRESSOR -

HAND AND THERE ARE METAL CHIPS

CONTINUED

IN THE OIL PUMP TO OIL COOLER

FLUID FILTER.

This section contains troubleshooting to locate and correct the cause(s)

of binding in the AGB gear train when turned by hand, and when metal

chips are present in the oil pump to oil cooler fluid filter. The AGB is

coupled to the high pressure compressor in the forward engine module

through a gearshaft. If there is damage to the high pressure compressor,

forward engine module position No. 3, 4, 11 or 12 bearing, or AGB gears

and/or bearings, binding will be felt when the AGB gear train is turned

by hand. T h e l u b r i c a t i o n s y s t e m d e l i v e r s h o t o i l , s c a v e n g e d f r o m b e a r i n g

packages throughout the engine, t h r o u g h a f l u i d f i l t e r t o t h e e n g i n e o i l

cooler. The cooled oil is then returned to the oil tank. Whenever metal

chips are generated, the fluid filter will catch and retain most of the

c h i p s . Based on the above description, it would be logical to assume

that forward engine module bearings may be faulty or that one of the AGB

gears or bearings has failed. In either case, the AGB magnetic plug

should also be more than one half covered with metal chips, unless it

was already wiped clean. T h e a r t o n t h i s p a g e p r o v i d e s a n o v e r v i e w o f

the systems described above. R e f e r t o t h i s p a g e a l o n g w i t h i n - t e x t a r t

while performing troubleshooting.

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