OPERATION157
heard,orwhentheenginespeedfallsbyapproximately200rpm.Depressingtheclutch
maynotbenecessarytobreakthedrivelinetorque,butthiswillvarywithroadandload
conditions.
ToupshiftfromaHI-splitgeartothenexthighergear’sLO-split(inthesamerange),
acceleratetheenginetogovernedspeed,thenmovethesplitterswitchtoLOasyoumove
theshiftleverthroughNEUTRALtothenexthighergear.Notethatthesplitterswitchmust
notbeactuateddowntotheLOpositionuntilthemainboxisinNEUTRAL.
Downshift—ShiftfromeighthHI-splittoeighthLO-split,thenseventhHI-split,seventh
LO-splitandsoon(double-clutchingbetweenthegears),untilyoureachfthLO-split.
TocontinuewhileinfthgearLO-split,iptherangeselectordowntoLOrange(preselect),
andasyoumovethegearshiftleverthroughNEUTRALtofourthgear,movethesplitter
switchfromLOtoHI.AstheshiftlevermovesthroughNEUTRAL,therangeshifttoLO
willbecompleted.YouarenowinfourthgearHI-split(LOrange).Continuedownshifting,
usingtheshiftleverandsplitterinthenormalmanner,untilyoureachLOspeedgear(LO
range,LO-split).
TodownshiftfromHI-splittoLO-split(inthesamegear)asenginespeedfalls,movethe
splittertoLO(preselect),thenreleaseandreapplytheacceleratorpedal.Anaudibleshift
completionshouldbeheard.
TodownshiftfromaLO-splitgeartothenextlowergear’sHI-split(inthesamerange)
asenginespeedfalls,movethesplitterswitchtoHIasyoumovetheshiftleverthrough
NEUTRALtothenextlowergear.Notethatthesplitterswitchmustnotbeactuatedupto
theHIpositionuntilthemainboxisinNEUTRAL.Remembertodouble-clutchbetween
gearsusingtheacceleratorpedaltosynchronizethetransmissioncomponents.
T31821andT318L21Reverse—ReversecanbeusedinLOrangeonly.
T318LR21Reverse—ReversecanbeusedinLOandHIrange.
T
omakearangeshiftinreverse,bringthetrucktoacompletestop.Fliptherangeselector
totherangedesired(preselect).MovetheshiftleveroutofreversethroughNEUTRAL,
andthenbackintoreverseagain.AsthelevermovesthroughNEUTRAL,therangeshift
willbecompleted.
CAUTION
Toavoidtransmissiondamage,doNOT
changerangewhilemovinginREVERSE.