Mack T313-T313L-T313Lr Shifting Instructions - Mack Granite GU Series Operator's Handbook Manual

214 OPERATION

MACK T313-T313L-T313LR Shifting Instructions

CAUTION
Make sure air pressure is at least 90 psi and unit is at operating temperature 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 T313(L)(LR) is a range-shifted transmission with 12 forward highway
speeds and an extra LO gear in the LO range. LO and HI ranges are
controlled by an air-shift range selector.
Note: When making a SPLIT SHIFT from gear to gear, the splitter switch must not
be actuated, either up or down, until the main box is in NEUTRAL. When making
a SPLIT SHIFT in the same gear to a preselected gear, especially under a heavy
load, the splitter will not shift until the driveline torque is relieved. This can be done
by depressing the clutch pedal and releasing it, or by backing off the throttle and
reapplying it. The splitter switch must not be actuated, either up or down, until
IMMEDIATELY before the driveline torque is relieved. When making a RANGE
SHIFT, it is important to preselect the range shift. This means that the range selector
must be moved to its next position (up or down) BEFORE the gearshift lever is
moved. Then move the gearshift lever through NEUTRAL to the next desired gear
position. As the lever passes through NEUTRAL, the range shift will be completed.
CAUTION
Do not "play" with the splitter and range selector tabs at a stop light, flipping from
high to low range or HI-LO split. These controls are not intended for entertainment.
Such activity can adversely impact the life of the transmission.
Upshift — For purposes of explaining the shifting procedures through ALL
gears, assume that the vehicle has a full load and will climb a slight grade.
Before moving the vehicle, the range selector must be in LO range and the
splitter switch in LO-split. With the shift lever in NEUTRAL, move the splitter to
LO-split (if needed), then the range to LO range (if needed).