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

TM 9-2835-255-34

3-2. TROUBLESHOOTING - CONTINUED

a. ACCESSORY GEARBOX (AGB) AND

(7) ES-7. AGB GEAR TRAIN TURNS

HIGH PRESSURE COMPRESSOR -

UNEVENLY (BINDS) WHEN TURNED BY

CONTINUED

HAND, LOW PRESSURE COMPRESSOR

RUBS OR BINDS WHEN TURNED BY

HAND AND MORE THAN ONE HALF OF

AGB MAGNETIC PLUG IS COVERED

W I T H METAL CHIPS.

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

of AGB gear train binding and low pressure compressor rubbing or binding

when more than one half of the AGB magnetic plug is covered with metal

chips. 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 positi.on 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. I f t h e r e i s d a m a g e t o t h e l o w p r e s s u r e c o m p r e s s o r o r

bearings in the forward engine module, or to the low pressure turbine

rotor or position No. 5 bearing in the rear engine subassembly, binding

will be felt when the low pressure compressor is turned by hand. The low

pressure turbine shaft normally runs inside of the high pressure

compressor shaft without making contact. If a bearing supporting the

high pressure compressor, low pressure compressor or low pressure

t u r b i n e r o t o r f a i l s , contact may occur between the two shafts. Binding

will be felt when these assembles are rotated by hand. Metal chips on

the AGB magnetic plug indicate a bearing has failed. The art on this

page provides an overview of the high pressure compressor, low pressure

compressor, low pressure turbine and AGB gear train systems. Refer to

this page along with in-text art while performing troubleshooting.

3-50

Change 5