TM 5-3810-300-24&P-3
7.4 Tachometer Drive
Tachometer Drive
A tachometer drive shaft may be installed at any one of
a. If threads (5/16"-24 or 3/8"-24) are provided on the
several locations on the engine.
outer end of the tachometer drive shaft to
accommodate a removing tool, thread remover J
At the front end of the engine, the tachometer drive shaft
5901-3 on the shaft; then attach slide hammer J
is pressed into the end of the camshaft or balance shaft
2619 to the remover. A few sharp blows of the
and extends through an adaptor attached to the balance
weight against the slide hammer rod will remove the
weight cover.
tachometer drive shaft.
The tachometer drive shaft may be installed in the end of
b. If threads are not provided on the outer end of the
either the camshaft, balance shaft or the blower drive
tachometer drive shaft, or if the end of the shaft is
shaft. A tachometer drive shaft adaptor is attached to
broken off, drill and tap the shaft. Then thread a
the flywheel housing cover or the blower rear end plate
stud into the shaft and remove the shaft with the
cover.
Where required, a tachometer drive cable
remover and slide hammer.
adaptor is used to change the speed or to change
direction of rotation, depending upon the location of the
CAUTION: Use adequate protective measures to
tachometer drive. A special key is used to connect the
prevent the metal particles from falling into the gear
drive shaft to the tachometer drive cable adaptor.
train and oil pan.
Remove Tachometer Drive
1. Start the tachometer drive shaft in the end of the
If replacement is necessary, remove the tachometer
camshaft or blower drive shaft. Then, using a suitable
drive shaft as follows:
sleeve, tap or press against the shoulder on the
tachometer drive shaft until the shoulder contacts the
1. Disconnect the tachometer drive cable from the
camshaft or blower drive shaft.
tachometer drive cable adaptor.
2.
Install the blower drive shaft.
2. If used, remove the tachometer drive cable adaptor
and key (key and seal assembly if the tachometer drive
3. Install the tachometer drive cover and adaptor on
shaft is driven by the-blower drive shaft).
the flywheel housing. Use a new gasket.
3. Remove the tachometer drive shaft adaptor and
4. Align the tachometer drive cover and adaptor with
gasket from the balance weight cover if the tachometer
the tachometer drive shaft as outlined in Section 7.0.
drive is located at the front of the engine. For a rear
5. Install the oil seal and key assembly (blower drive
mounted tachometer drive, remove the flywheel housing
shaft driven tachometer drive).
cover and adaptor assembly and gasket. Examine the
6. If used, install the tachometer drive cable adaptor
oil seal(s), if used, for wear or damage. Replace the oil
and key. Lubricate the tachometer drive cable adaptor
seal (camshaft drive) or oil seal unit (blower drive shaft
with grease through the fitting provided.
drive), if necessary.
7. Attach the tachometer drive cable.
4. If the tachometer drive shaft is driven by the blower
drive shaft, remove the blower drive shaft.
5. Remove a tachometer drive shaft that is pressed
into the camshaft as follows: Install Tachometer Drive
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