TM 5-3820-233-35/1
(4) Gear train noise usually indicates ex-
cessive gear lash, scoring, pitting or bearing
wear. A rattling noise is an indication of ex-
cessive gear lash, whereas a whining noise is
a result of too little gear lash. The correct
backlash for the gear train is 0.003 to 0.008
inch.
d. Installation. Reverse the steps 1 through
7 under "Gear train removal".
in the gear train with the timing marks (O-O and
R-R) as indicated.
52. Crankshaft and Main Bearings
a. General. The crankshaft assembly is lo-
cated at the bottom of the cylinder block, and
is supported by five main bearings. The main
bearings are of the replaceable type and are
used at each journal. A main bearing consists
of two shells. The upper shell is located in
crankcase main bearing support and the low-
er shell is seated in the main bearing cap.
b. Removal
(1) Drain the engine oil (Operator's
Manual).
Figure 24-6. Checking flywheel housing
(2) Remove the power unit (para 24).
concentricity.
(3) Remove the muffler air cleaner (Op-
erator's Manual).
b. Removal
(4) Remove the hoods, side panels, and
(1) Remove the power unit (para 24).
tie rods (Operator's Manual).
(2) Refer to the Operator's Manual and
( 5 ) Drain the cooling system.
remove the muffler and air cleaner.
(6) Remove the radiator (para 32).
(3) Refer to the Operator's Manual and
(7) R e m o v e t h e f l y w h e e l a n d f l y w h e e l
remove the hoods, side panels, and tie rods.
housing (para 47).
(4) Remove the flywheel and flywheel
(8) Remove the cylinder head (para 42).
housing (para 47).
(9) R e m o v e t h e o i l p a n ( p a r a 4 3 ) .
(5) Remove the blower drive gear (para
(10) R e m o v e t h e l u b r i c a t i n g o i l p u m p
36).
and pressure regulator (para 44).
(6) Remove the crankshaft gear (para
(11) Remove the pistons and connecting
52).
rods (para 45).
(7) Remove the camshaft and balancer
(12) Remove the crankshaft pulley and
shaft gears, and idler gear assembly, (para
front cover (para 48).
50).
(13) Refer to figure 28-1 and remove the
c. Cleaning, Inspection, and Repair
crankshaft and main bearing.
(1) Clean all parts with an approved
c. Disassembly. Disassemble the crankshaft
cleaning solvent and dry thoroughly.
and main bearings in the numerical sequence
(2) Inspect idler gear for chipped teeth
as illustrated on figure 28-2.
and wear. Replace a defective gear.
d. Cleaning, Inspection, and Repair
(3) Inspect idler gear bearing for
(1) Clean all parts with an approved
scoring, pitting, wear, and overheating. Re-
cleaning solvent and dry thoroughly.
place a defective bearing.
3-44
