Mack CSM 2010, Operator'S Handbook Manual

Page: 151 / 232

OPERATION 143
MACK T310 Shifting Instructions
CAUTION
Make sure air pressure is at least 620
kPa (90 psi) and unit is warmed before
making range shifts. Always start in LO
range. This also applies to dynamometer
testing. When the truck is stationary, do
NOT shift into HI range and then start
moving the truck. Otherwise, damage to
the synchronizer may result.
The T310 unit is a range-shifted transmission which has 10 forward "highway" speeds.
This transmission features a LO and HI auxiliary compound section controlled by an air
shift range selector located on the shift lever. The compound section is equipped with a
synchronizer to facilitate LO-/HI- range shifting.
The LO range provides five low ratios. Never attempt to move the vehicle from a stopped
position in any gear higher than fourth speed gear. Depending on load, grade, or road
conditions, it may be necessary to start in first, second, third or fourth speed gears. In HI
range there are five forward gears that can be shifted in the standard manner. Always
remember, however, to double clutch whether moving up or down through these gears.
Reverse gear can be used in LO range only.
Upshift —
With the shift lever in NEUTRAL, flip the air shift range selector down to
LO range. Then shift the transmission into first gear. Shift up to second, third, fourth and
fifth speed gears, double clutching between the gears. When maximum engine RPM has
been reached in fifth gear, flip the air shift range selector up to HI range (preselect). Then
move the shift lever through NEUTRAL to sixth gear. As the shift lever passes through
NEUTRAL, the transmission is placed into Hi range. Continue following the normal
sequence (7-8-9-10), being sure to double clutch from one gear to the next.
Downshift — Shift from 10th speed gear down through the HI range (9-8-7-6), double
clutching through each gear. While still in sixth speed gear, flip the air shift range selector
down to LO range (preselect). Then move the shift lever through NEUTRAL to fifth speed
gear. As the shift lever passes through NEUTRAL, the transmission is placed into LO range.
Then, shift down to fourth, third, second and first speed gears, double clutching between
all gears.