freightliner Columbia Driver Manual page 113

2. Use the clutch brake to stop gear rotation when
shifting into 1st or reverse when the vehicle is
stationary. The clutch brake is actuated by de-
pressing the clutch pedal all the way to the floor.
For normal upshifts and downshifts, only a partial
disengagement of the clutch is necessary to
break engine torque.
3. Do not make splitter shifts with the vehicle mov-
ing in reverse gear.
4. The shift lever should not be moved to the center
or left rail positions at vehicle speeds above 40
mph (65 km/h).
5. Double-clutch between all upshifts and down-
shifts.
6. After your shifting ability improves, you may want
to skip some of the ratios. This may be done
only when operating conditions permit, depend-
ing on the load, grade, and road speed.
7. Avoid hunting for neutral by moving the gear shift
lever from the left rail to right rail. This action can
cause excessive transmission wear.
Upshifting
1. Position the gear shift lever in neutral. Start the
engine, and bring the air system pressure up to
100 to 120 psi (689 to 827 kPa).
2.
Press the clutch pedal to the floor. Shift into 1st
gear, then engage the clutch, with the engine at
or near idle speed, to start the vehicle moving.
3.
Button-only shift—Preselect the next gear by
sliding the shift button forward. Break torque by
releasing the throttle or by depressing the clutch
pedal. Decrease engine speed to synchronize
the engine speed with the transmission speed.
The shift will complete when the engine rpm has
decreased to the proper speed.
The button-only shift is used for gear changes
from 1st to 2nd, 3rd to 4th, 5th to 6th, 7th to 8th,
and 9th to 10th.
4. Lever-only shift—Break torque by releasing the
throttle and depressing the clutch pedal. Double-
clutching, move the shift lever to the next desired
gear position. Decrease engine speed to syn-
chronize the engine speed with the transmission
speed. The shift will complete when the engine
rpm has decreased to the proper speed.
The lever-only shift is used to skip a full gear.
With the shift button rearward—1st to 3rd, 3rd to
5th, 5th to 7th, and 7th to 9th. With the shift but-
ton forward—2nd to 4th, 4th to 6th, 6th to 8th,
8th to 10th.
NOTE: Lever-only shifts skip an entire gear ratio
and will require the engine rpm to decrease
twice the amount of a normal shift.
5.
Combination button/lever shift—Preselect the
next gear by sliding the shift button rearward.
Break torque by releasing the throttle and de-
pressing the clutch pedal. Double-clutch and
move the shift lever to the next desired gear po-
sition.
The combination button/lever shift is used for
gear changes from 2nd to 3rd, 4th to 5th, 6th to
7th and 8th to 9th.
Downshifting
CAUTION
Do not attempt a button-only downshift at too
high an engine speed (generally above 1400
rpm). Doing so could result in damage to the en-
gine, transmission, and/or driveline.
1. Button-only shift—With the throttle still applied,
preselect the next gear by sliding the shift button
rearward. Break torque by releasing the throttle
or by depressing the clutch pedal. Increase en-
gine speed to synchronize the engine speed with
the transmission speed. The shift will complete
when the engine rpm has increased to the
proper speed.
The button-only shift is used for gear changes
from 10th to 9th, 8th to 7th, 6th to 5th, 4th to 3rd,
and 2nd to 1st.
CAUTION
Do not attempt a lever-only downshift at too high
an engine speed (generally above 1000 rpm).
Doing so could result in damage to the engine,
transmission, and/or driveline.
2. Lever-only shift—Break torque by releasing the
throttle and depressing the clutch pedal. Double-
clutching, move the shift lever to the next desired
gear position.
Transmissions
8.16