TM 5-6115-400-35
prior to pressing it into the cover. The
(2) The gear train will run quietly if the gears
seal I.D, has a layer of rubber compound
and bearings are in good condition. The
to prevent oil leakage between the seal
specified backlash between mating gears
and the crankshaft.
is given in Table I. As the gears or the
(a) Place cover on a flat surface with
bearings wear, the backlash will increase
the front side to the top as shown ,in
and the gear train may become noisy.
New parts should be installed when the
(b) Position seal in cover with open
bachlash between any two mating gears
side of seal facing down and
exceeds .020 inch.
positioned squarely in bore of cover.
(3) The gear train may be exposed by
Caution. Make certain seal is
removing the timing gear housing cover
not cocked in cover bore.
as described in paragraph 48.
(c) Drive or press seal into cover bore
b. Camshaft Gear Removal and Installation. To
the specified distance of 2 5/32
prevent possible damage to the flywheel housing when
inches-2 11/64 inches, as shown in
installing the camshaft gear, it is recommended that the
camshaft be removed from the engine before removing
shown will properly position the seal
the gear. Refer to paragraph 55. If gear is to be
the correct distance in the cover
bore, and will place the driving force
on the outer edge of the seal.
Caution. Do not press on open
face of seal or seal damage will
result.
(d) After seal is positioned in cover,
insert fingers into inner part of seal
and check for rotation. If seal was
installed properly, the inner part will
turn with a firm feel to the fingers.
49. Gear Train and Timing Gear Housing
a. General.
(1) Located in the timing gear housing at the
front end of the engine is a completely
enclosed train of four helical gears as
shown in figure 74. The crankshaft gear,
which is pressed and keyed onto the
crankshaft, drives the camshaft gear and
the lubricating oil pump driving gear. The
camshaft gear drives the accessory drive
gear. The gear train is splash-lubricated
by oil thrown by the gears, and also by oil
returning to the oil pan from the accessory
drive and the camshaft gear.
Figure 74. Gear train.
106
