TM 9-2320-283-10
3. When starting a downgrade, select the gear range you would most likely use
if you were climbing that same grade. If too much braking occurs select a
lower setting with the ENGINE RETARDER switch or shift to a higher gear
range. If not enough braking, select a higher setting with the ENGINE
RETARDER switch or shift to a lower gear range.
4. The engine retarder is very effective on ice, snow or slick roads by selecting
a higher than normal gear range for the road speed. This will reduce rpm and
provide lower engine braking. But first try selecting a lower setting with the
ENGINE RETARDER switch. Engagement of differential lockup may also be
helpful on slick surfaces (refer to instructions on using the Interaxle Differen-
tial Lock-up system).
REVIEW OF DRIVING GUIDELINES
a. After prolonged engine idle, run the engine up to full rpm momentarily to clean
engine.
b. The most practical engine rpm cruising speed for the highway is one that per-
mits the legal road speed and also fuel economy. The recommended cruising
range for the highway is 1,800 to 1,900 rpm.
c. In the city and other reduced speed zones, match engine speed to the lower
load requirement to conserve fuel and lower vehicle noise level. Select a gear
range that permits operating in the area of not less than 1,500 rpm.
d. When manually downshifting for power on a grade, wait for your shift points
before making the shift. You will save both time and fuel if you do. If you main-
tain a satisfactory engine speed on a grade in your cruising gear, it is not necessary
to downshift at all.
e. Avoid overspeeding the engine. Never allow the engine to be pushed above
governed rpm when rolling down a grade.
f. Progressive downshifting, when starting down grade from the top of a hill, will
provide better control around curves and turns, and will save brakes.
USING TRAILER BRAKE HAND CONTROL
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