freightliner 108SD, Руководство пользователя

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fall outside of the acceptable range to perform a
shift. If the shift is denied, a tone will sound.
Manual Mode (MAN)
In manual mode (MAN), the driver selects upshifts
and downshifts instead of letting the UltraShift PLUS
select them automatically. Manual shifting may be
helpful when traversing a work site, railroad tracks,
or steep grades, for example. To drive forward, press
in the neutral lock button, move the selector switch to
Drive (D), and press down on the throttle pedal. To
shift up, pull the lever up (towards you); to shift
down, push the lever down (away from you). The
system holds the current gear unless a shift is re-
quested or if the system initiates a manual mode
override.
NOTE: The transmission may deny a shift while
ascending or descending a grade if the load of
the vehicle and grade of the terrain in combina-
tion with the drivetrain ratio and engine torque
fall outside of the acceptable range to perform a
shift. If the shift is denied, a tone will sound.
NOTE: If attempting to select a non-Neutral
mode without applying the service brakes, the
transmission will not shift into gear. To shift into
gear, select Neutral, apply the service brakes,
and select the desired mode again.
Manual Mode Override
The system is equipped with a manual mode over-
ride function. If the vehicle is being "back driven" (for
example, descending a grade and vehicle speed ex-
ceeds engine speed) and the engine speed is exces-
sively high, the system will upshift automatically.
Also, if the start gear is changed and it causes the
engine to lug at takeoff, the system will override the
current position and select the best available gear.
Low (L)
Low (L) is at the lower end of the four-position selec-
tor switch located at the end of the SmartShift con-
trol. Use Low when wanting to maximize engine
braking and minimize the use of the brake pedal—for
example, when driving down long grades or when
coming to a stop. To select Low, press in the neutral
lock button and move the selector switch to the L
position. The lowest available start gear will be se-
lected (the starting gear cannot be changed in Low).
If Low is selected while moving, the transmission will
not upshift (unless the system initiates a Low over-
ride). The system will downshift at the earliest oppor-
tunity to provide maximum engine braking.
NOTE: If attempting to select a non-Neutral
mode without applying the service brakes, the
transmission will not shift into gear. To shift into
gear, select Neutral, apply the service brakes,
and select the desired mode again.
Low Override
The system is equipped with a Low override function.
If the vehicle is being "back driven" (for example, de-
scending a grade and vehicle speed exceeds engine
speed) and the engine speed is excessively high, the
system will upshift automatically. Also, if the start
gear is changed and it causes the engine to lug at
takeoff, the system will override the current position
and upshift.
Clutch Abuse Protection
Although a vehicle equipped with an UltraShift PLUS
uses an automated clutch, the clutch can still over-
heat and slip with improper use. The clutch abuse
protection feature helps protect the clutch if the auto-
mated clutch starts to overheat. When the clutch
abuse protection feature initiates and sounds a warn-
ing tone, full clutch actuation must be completed
quickly. If it is not completed quickly enough, the sys-
tem will either open the clutch (if the throttle pedal is
not being pressed) or close the clutch (if the throttle
pedal is being pressed). If the abuse continues, the
system will open the clutch and take away throttle
control briefly to allow the clutch to cool down.
To protect the clutch:
•
Select the lowest possible start gear for the
application.
•
Use Creep Mode when appropriate.
•
Use the service brakes and the Hill Start Aid
when launching on a grade.
•
Minimize the time it takes to engage the clutch
from rest.
•
Do not use the throttle to hold the vehicle on a
grade; use the service brakes.
Automated and Automatic Transmissions
14.8