MACK T31321 and T313LR21 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.

The T313(LR)21 a range - shifted transmission with forward highway speeds and extra gear the range. and ranges are controlled air - shift range selector .

Note: When making a SPLIT SHIFT from gear gear , the splitter switch must not actuated, either down, until the main box NEUTRAL. When making a SPLIT SHIFT the same gear a preselected gear , especially under a heavy load, 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.

Before moving the the range selector must range and the splitter switch - With the shift lever move the splitter - split (if then the range range (if

Refer the shift pattern and move the shift lever speed gear (LO range,split). Apply accelerator , engage the clutch, and accelerate governed speed. Shift through first, second, third - fourth speed gears, double - clutching between the gears.

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

T o upshift from - split - split (in the same accelerate the engine governed speed, move the splitter switch depress the clutch and back f the accelerator Reapply the accelerator and engage the clutch when the audible shift when the engine speed falls approximately 200 Depressing the clutch may not necessary break the driveline but this will vary with road and load

T o upshift from a - split gear the next higher gear ’ s - split (in range), accelerate the engine governed speed, then move the splitter switch you move the shift lever through NEUTRAL the next higher gear . Note that the splitter switch must not actuated down the position until the main box

Downshift Shift from eighth - split eighthsplit, then seventhsplit, seventh - split and (double - clutching between the gears), until you reach fifthsplit.

While fifth gear - flip the range selector down range then move the shift lever through NEUTRAL fourth gear (double - clutch and use the throttle the normal manner between the shift lever moves through the range shift will Y are now fourth gear - split (LO Continue using the shift lever the normal manner until you reach speed gear (LO -

T o downshift from - split - split (in the same gear) engine speed falls, move the splitter (preselect), then release and reapply the accelerator pedal. audible shift completion should heard.

T o downshift from a - split gear the next lower gears - split (in range) engine speed move the splitter switch you move the shift lever through NEUTRAL the next lower gear Note that the splitter switch must not actuated the position until the main box Remember double - clutch between gears.

T31321 Reverse — Reverse can used range only

T313LR21 Reverse Reverse can used and range.

T o m a k e a r a n g e s h i f t i n r e v e r s e , bring the truck a complete Flip the range selector the range desired Move the shift lever out reverse through and then back into reverse the lever moves through the range shift will

Caution

T o avoid transmission damage, NOT change range while moving