Mack T310 Shifting Instructions - Mack Granite GU Series Operator's Handbook Manual

208 OPERATION

MACK T310 Shifting Instructions

CAUTION
Make sure air pressure is at least 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.