TM 5-3810-307-10
b.
As you upshift, increase the crane speed with a progressive increase in
engine rpm. It should seldom be necessary to reach governed speed in the
lower gears except in peak load situations such as starting up a grade.
c.
Maintain a reasonable rate of speed when climbing a grade and preplan the
climb whenever possible. Gradually depress the throttle to maintain
governed rpm and remain at full throttle as the crane starts up the grade. If
there is sufficient power to maintain satisfactory speed without the engine
laboring, remain in that gear for the entire grade.
d.
If the engine starts to labor, ease the throttle off a bit to allow the
transmission to shift into the next lower gear. Make the shift quickly because
the speed will usually drop quickly when shifting.
NOTE
Going downhill, the engine provides the most efficient
braking when at or near top rpm in operating range,
however, the governor has no control over the engine
speed when it is being pushed by a heavy crane.
e.
If the engine exceeds governed rpm when descending a grade, engine
overspeed can result in serious damage. Use both the vehicle brakes and
gears in combination to keep the crane speed under control.
f.
Continue to monitor the Transmission OIL TEMPerature Gauge (19) when
the ambient temperature is high and in particular, when traveling up an
extended or steep grade. If the transmission oil temperature continues to
rise, manually downshift to the next lower gear.
The following information outlines proper shift points when in a manual (emergency)
mode.
To avoid hard shifting, the road speeds at which the shift should be made are shown
on the following chart.
Shift Points at MPH/KPH
Speed
Gear Upshift
MPH
KPH
Gear Downshift
2nd to 1st
8
5
1st to 2nd
3rd to 2nd
11
7
2nd to 3rd
4th to 3rd
19
12
3rd to 4th
5th to 4th
28
17
4th to 5th
6th to 5th
57
36
5th to 6th
Stepping of changes should be progressive. No attempt should be made to upshift
2 gears or more at a time. It is not always necessary to start a crane in 1st gear. Up to 3rd gear
may be used when starting on reasonably level terrain.
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