Allison Transmission 4430 OFS

LISTOFWARNINGS(cont'd)
Thismanualcontainsthefollowingwarnings—
ITISYOURRESPONSIBILITYTOBEFAMILIARWITHALLOFTHEM.
•D(Drive)maynotbeattainedduetoanactiveinhibitor.
AlwaysapplytheservicebrakeswhenselectingD(Drive)to
preventunexpectedvehiclemovementandbecauseaservice
inhibitmaybepresent.Whentheselectedrangeisashing,
itindicatestheshifttoD(Drive)isinhibited.Determineif
diagnosticcodesareactiveifD(Drive)isnotattained.Refer
to7.5SELECTORDISPLAYDESCRIPTIONSFORACTIVE
DIAGNOSTICTROUBLECODES(DTCs)ANDINHIBITS.
•Toavoidlossofcontrol,useacombinationofdownshifting,
braking,andotherretardingdevices.Downshiftingtoalower
transmissionrangeincreasesenginebrakingandcanhelp
youmaintaincontrol.Thetransmissionhasafeatureto
preventautomaticupshiftingabovethelowerrangeselected.
However,duringdownhilloperation,ifenginegovernedspeed
isexceededinthelowerrange,thetransmissionwillupshift
tothenexthigherrangetopreventenginedamage.Thiswill
reduceenginebrakingandcouldcausealossofcontrol.
Applythevehiclebrakesorotherretardingdevicetoprevent
exceedingenginegovernedspeedinthelowerrangeselected.
11