Operation
Toactivatetheenginebrake,pressthepushbutton
ENGBRAKEON/OFFswitchonthesteeringwheel
(pressingthisswitchagainwilldeactivatethesystem).
TheENGINEBRAKESELECTOR1/2/3switchisthen
usedtoadjusttheamountofbrakingapplied.
Usingenginebrakingfeaturescanextendbrakelining
life.Thefeaturesalsoallowthedrivertoslowthevehicledown
ormaintainaconstantspeedonsteeproadgradesthatwould
otherwiseresultinprolongeduseoftheservicebrake,which
couldcausebrakefade.RefertotheEngineOperationand
MaintenanceManualfordetailedinformationontheengine
brakingsystem.
EngineBrakeWithAllisonTransmissions
WhentheTransmissionControlModule(TCM)detectsthe
enginebrakehasbeenenabled,itcommandsuseofa
preselectedshiftscheduleinordertoenhancetheenginebrake
performance.
EngineBrakeWithEaton
®
AutoShift
®
/UltraShift
®
Transmissions
SpecialDriverInstructions
Lowormanualtransmissionmodecanbeusedtomaximize
enginebrakeperformance.
•Keepenginespeedascloseto2250RPMaspossible.
•Maintainbrakepedalapplicationuntilanydesired
downshiftsarecompleted.Failuretodosomaycause
missedshifts.
•Thegeardisplayontheshiftselectorwillstopblinking
whenthedownshiftiscompleted,andthedriverwillnotice
resumptionofenginebrakingasanindicationthatthe
shiftiscompleted.
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