AGB GEAR TRAIN TURNS UNEVENLY (BINDS) WHEN TURNED BY HAND AND LOW PRESSURE COMPRESSOR RUBS OR BINDS WHEN TURNED BY HAND

TM 9-2835-255-34

3-2. TROUBLBSHOOTING - CONTINUED

a. ACCESSORY GEARBOX (AGB) AND

(3) ES-3. AGB GEAR TRAIN TURNS

HIGH PRESSURE COMPRESSOR -

UNEVENLY (BINDS) WHEN TURNED BY

CONTINUED

HAND AND LOW PRESSURE COMPRESSOR

RUBS OR BINDS WHEN TURNED BY

HAND. NO OTHER ROTATION OR METAL

CHIPS NOTED.

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

of AGB gear train binding when turned by hand, and low pressure

compressor rubbing or binding when turned by hand. 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. The low pressure compressor is mechanically coupled to the low

pressure turbine rotor in the rear engine subassembly. If there is

damage to the low pressure compressor or position No. 1 or 2 bearing in

the forward engine module, o r t o t h e l o w p r e s s u r e t u r b i n e r o t o r o r

position No. 5 bearing in the rear engine subassembly, binding will be

f e l t w h e n t h e low pressure compressor is turned by hand. The AGB and

high pressure compressor assemblies have no mechanical connection with

the low pressure compressor and low pressure turbine assemblies. This

symptom indicates that two separate failures or one failure causing

collateral damage has occurred. The art on this page provides an

overview of the AGB gear train/high pressure compressor and low pressure

compressor/low pressure turbine systems. Refer to this page along with

the in-text art while performing troubleshooting.

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