TM 5-3810-300-24&P-3
three 3/8"-16 bolts. Tighten the bolts to 25-40 lb-ft
torque.
2. With these marks in alignment, start the idler gear
into mesh with the crankshaft gear and either the
3. Clamp the idler gear assembly and fixture in vise as
camshaft or balance shaft gear, and simultaneously
shown in Fig. 7.
rotate the gear hub so that the hollow pin at the inner
face of the hub nearly registers with the oil hole in
4. Attach the cord to the idler gear and spring scale and
the end plate.
check the pre-load as outlined in item 4 of the first
method.
3. Roll the idler gear into position, align the hollow pin
with the hole in the end plate, and gently tap the hub
If the scale reading is within the specified 1-1/4 to 6-3/4
until it seats against the end plate. Thus the hollow
lbs., but fluctuates more than the permissible 2 lbs. 11
dowel pin in the hub will conduct oil through the end
ounces, the idler gear and bearing assembly must NOT
plate and into the hub where it flows through a drilled
be installed on the engine. Fluctuations in scale reading
passage to the roller bearing.
may be caused by the races not being concentric to each
other, damaged races or rollers, or dirt or foreign
4. After making sure that the hub is tight against the
material within the bearings. In these cases, the bearing
end plate, secure the idler gear assembly in place
should be inspected for the cause of fluctuation in the
with a "-13 bolt and special washer. Tighten the
scale readings and corrected or a new bearing installed.
bolt to 80-90 lb-ft torque (cast iron cylinder block).
A scale reading which exceeds the specified maxi-mum
5.
If previously removed, install the idler gear hole
indicates binding of the bearing rollers, or rollers
spacer (dummy hub). Secure the spacer to the
improperly installed. When the scale reading is less than
cylinder block end plate and cylinder block with a "-
the specified minimum, the bearing is more likely worn
13 bolt and special washer. Tighten the bolt to 80-90
and should be replaced.
lb-ft torque (cast iron cylinder block).
After the pre-load test is completed, remove the steel
CAUTION: Current engines use a new idler
plates and attach bearing retainer as follows:
gear hub and idler gear hole spacer (dummy
hub) which requires "-13 x 2 " retaining
1. Attach the bearing retainer to the idler gear with six
bolts, re-placing the "-13 x 2" bolts formerly
bolts and three bolt locks. Tighten the bolts to 24-29
used.
lb-ft torque.
6. Lubricate the idler gear and bearing liberally with
2. Bend the ears of each bolt lock against the flat side
clean engine oil.
of the attaching bolt heads to secure the bolts.
7. Check the backlash between the mating gears. The
NOTE: Idler gear assemblies which have a
backlash must be .003" to .008" between new gears
total length of 1. 514" to 1. 519" are to be
and must not exceed .010" between used gears.
used ONLY on engines equipped with a cast
iron flywheel housing. Idler gear assemblies
8. No gasket is used between the idler gear assembly
with a total length of 1.509" to 1.514" are used
and the flywheel housing.
on engines with an aluminum flywheel housing
and may also be used with cast iron housings.
NOTE: Make sure the oil passage in the
cylinder block is plugged at the dummy hub
Install Idler Gear, Hub and Bearing Assembly
location.
1. Position the crankshaft gear and either the balance
9. Install the flywheel housing as outlined in Section
shaft or camshaft gear (depending upon engine
rotation) so that the match marks will align with those
on the idler gear (see Fig. 1 Section 1.7.2).
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