operators_manual

neutral also prevents proper transmission
component lubrication. During coasting the
transmission is driven by the rear wheels,
and the countershaft gear (which lubricates
the transmission components by oil splash)
will only be turning at idle speed.
Descending a Grade
WARNING
DO NOT hold the brake pedal down
too
long or too often while going down
a steep or long grade. This could
cause the brakes to overheat and re-
duce their effectiveness. As a result,
the vehicle will not slow down at the
usual rate. To reduce the risk of an ac-
cident which could cause personal in-
jury or death, before going down a
steep or long grade, reduce speed and
shift the transmission into a lower gear
to help control your vehicle speed.
Failure to follow procedures for proper
downhill operation could result in loss
of vehicle control.
Engine Overspeed
CAUTION
Do not let the engine RPM operate be-
yond
the maximum governed RPM.
Operating the engine above the maxi-
mum governed RPM may result in En-
gine damage.
NOTE
Often these recommendations are
secondary
to maintaining an adequate
and safe speed relative to the sur-
rounding traffic and road conditions.
Operate the engine within the optimum
engine rpm range and do not allow the
rpm's to exceed the maximum governed
speed. See your Engine Operation and
Maintenance manual for information
regarding engine rpm. When the engine is
used as a brake to control vehicle speed
(e.g., while driving down a grade), do not
allow the engine rpm to exceed maximum
governed speed. Under normal load and
road conditions operate the engine in the
lower end of the range.
The tachometer is an instrument that aids
in obtaining the best performance of the
engine and manual transmission, serving
as a guide for shifting gears. Refer to the
Engine Operation and Maintenance
manual for optimum engine rpm.
•
If the engine rpm moves beyond
the maximum governed speed,
indicating an overspeed condition,
apply the service brake or shift to a
higher gear to bring engine rpm
within the optimum speed range.
• When driving downhill: shift to a
lower gear, use the engine brake (if
so equipped), and use the service
brake, keeping the engine speed
below 2,100 rpm.
When the engine speed reaches its
maximum governed speed, the injection
pump governor cuts off fuel to the engine.
However, the governor has no control over
the engine rpm when it is being driven by
the vehicle's transmission, for example, on
steep downgrades. Apply service brakes or
shift to a higher gear. Fuel economy and
engine performance are also directly
related to driving habits:
• The best results in trip time and
fuel economy are obtained while
driving the vehicle at a steady
speed.
DRIVING - Driving Tips and Techniques
136 Y53-6096-1C1 (09/20)
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