MACK T31821, T318L21 and T318LR21 Shifting Instructions CAUTION

Make sur e air essur e least psi and unit operating temperatur e befor e making range shifts. Always start This also applies dynamometer testing. When the truck stationary , NOT shift into range and then start moving the damage the synchr onizer may r esult.

Note: When making a SPLIT SHIFT from gear gear , the splitter switch must not actuated, either down, until the main box When making a SPLIT SHIFT the same gear a preselected gear , especially under a heavy the splitter will not shift until the driveline torque This can done depressing the clutch pedal and releasing it, backing f the throttle and reapplying The splitter switch must not either until IMMEDIA TEL Y before the driveline torque relieved. When making a RANGE SHIFT , important preselect the range This means that the range selector must moved its next position (up down) BEFORE the gearshift lever Then move the gearshift lever through NEUTRAL the next desired gear position. the lever passes through NEUTRAL, the range shift will completed.

Upshift — For purposes explaining the shifting procedures through ALL gears, assume that the vehicle has a full load and will climb a slight grade.

T o prepare for moving the position the shift lever select - split using the splitter and select range using the range selector

Refer the shift pattern and move the shift lever speed gear (LO range,split). Apply accelerator and engage the clutch, then accelerate governed speed. Select the splitter switch (preselect) and release the accelerator pedal long enough for the split shift complete. Reapply the accelerator . Shift through firstsplit, firstsplit, secondsplit, second - split and on, until you reach fourthsplit. Remember double - clutch between gears.

T o continue while fourth gearsplit, flip the range selector range (preselect), and you move the shift lever through NEUTRAL fifth gear , move the splitter switch from LO. the lever moves through NEUTRAL, the range shift will completed. Y are now fifth gear - split (HI range). Continue shifting fifthsplit, sixthsplit, sixth - split and on, until you reach eighthsplit. Remember double - clutch between gears.