Mack CSM 2010 - MACK T31821, T318 L21 and T318 LR21 Shifting Instructions

156OPERATION
MACKT31821,T318L21andT318LR21Shifting
Instructions
CAUTION
Makesureairpressureisatleast620kPa(90psi)andunitisatoperatingtemperature
beforemakingrangeshifts.AlwaysstartinLOrange.Thisalsoappliestodynamometer
testing.Whenthetruckisstationary,doNOTshiftintoHIrangeandthenstartmoving
thetruck.Otherwise,damagetothesynchronizermayresult.
Note:WhenmakingaSPLITSHIFTFROMGEARTOGEAR,thesplitterswitchmustnot
beactuated,eitherupordown,untilthemainboxisinneutral.
WhenmakingaSPLITSHIFTINTHESAMEGEARtoapreselectedgear,especiallyunder
heavyload,thesplitterwillnotshiftuntilthedrivelinetorqueisrelieved.Thiscanbedone
bydepressingtheclutchpedalandreleasingit,orbybackingoffthethrottleandreapplying
it.Thesplitterswitchmustnotbeactuated,eitherupordown,untilIMMEDIA TELYbefore
thedrivelinetorqueisrelieved.
WhenmakingaRANGESHIFT,itisimportanttopreselecttherangeshift.Thismeansthat
therangeselectormustbemovedtoitsnextposition(upordown)BEFOREthegearshift
leverismoved.ThenmovethegearshiftleverthroughNEUTRALtothenextdesiredgear
position.AstheleverpassesthroughNEUTRAL,therangeshiftwillbecompleted.
Upshift—ForpurposesofexplainingtheshiftingproceduresthroughALLgears,assume
thatthevehiclehasafullloadandwillclimbaslightgrade.
Toprepareformovingthevehicle,positiontheshiftleverinNEUTRAL,selectLO-split
usingthesplitterswitch,andselectLOrangeusingtherangeselector.
RefertotheshiftpatternandmovetheshiftlevertoLOspeedgear(LOrange,LO-split).
Applyacceleratorandengagetheclutch,thenacceleratetogovernedspeed.SelectHI
onthesplitterswitch(preselect)andreleasetheacceleratorpedallongenoughforthe
splitshifttocomplete.Reapplytheaccelerator.ShiftthroughrstLO-split,rstHI-split,
secondLO-split,secondHI-splitandsoon,untilyoureachfourthHI-split.Remember
todouble-clutchbetweengears.
TocontinuewhileinfourthgearHI-split,iptherangeselectoruptoHIrange(preselect),
andasyoumovetheshiftleverthroughNEUTRALtofthgear,movethesplitterswitch
fromHItoLO.AsthelevermovesthroughNEUTRAL,therangeshifttoHIwillbe
completed.YouarenowinfthgearLO-split(HIrange).ContinueshiftingtofthHI-split,
sixthLO-split,sixthHI-splitandsoon,untilyoureacheighthHI-split.Rememberto
double-clutchbetweengears.
ToupshiftfromLO-splittoHI-split(inthesamegear),acceleratetheenginetogoverned
speed,movethesplitterswitchtoHI(preselect),depresstheclutchandbackoffthe
acceleratorpedal.Reapplytheacceleratorandengagetheclutchwhentheaudibleshiftis