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alsohaveadash-mountedlightthatilluminateswhenthesecondarymode

scheduleisactive.

Frequently,eitherperformanceoreconomyshiftpointsareselectedfor

theprimaryshiftschedule(reectingthemostcommonlyusedstateofthe

vehicle),andtheothersetofshiftpointsareselectedforthesecondaryshift

schedule.

TheprimaryandsecondaryshiftschedulesmustbespeciedwhentheTCM

isprogrammed.ThevehicleOEMdetermineswhichprimary/secondaryshift

schedulecombinationtheywouldlikethetransmissiontohavewhenthe

vehicleisbuilt.

4.2.5PERFORMANCE/ECONOMYSHIFTSCHEDULES(N/AforOFS

Models).Currently,AllisonTransmissionoffersthefollowingcommonly

availableshiftschedulestotheOEM(s):

•S1&S5-Performance:WOTupshiftsnearFullLoadGovernedSpeed

(FLGS)

•S2&S6-Performance:WOTupshiftsataxed(lessthan100)percent

ofFLGS

•S3&S7-Economy:Upshiftsatspeedswhichpullenginedownto

axedrpmaftertheshift

•S4&S8-Economy:Upshiftsatspeedswhichpullenginedowntoa

xedrpm(andlessthanS3)aftertheshift

•S9-Economy:Upshiftsanddownshiftsoccuratspeedsthatareeven

lowerthantheS4shiftstrategy

•SA-Economy:WOTupshiftsaresimilartoS1&S5.TheSA

part-throttleupshiftsanddownshiftsoccuratsignicantlylowerspeeds

thantheS5part-throttleshifts.

•SB-Economy:WOTupshiftsanddownshiftssimilartoSA.The

SBpart-throttleupshiftsoccuratslightlyhigherspeedsthantheSA

part-throttleupshifts.

•SC-Economy:WOTupshiftsaresimilartoS3&S7.TheSC

part-throttleandclosed-throttleupshiftsanddownshiftsaresimilarto

theSApart-throttleandclosed-throttleshifts.

•SD-Economy:WOTupshiftsanddownshiftssimilartoS3&S7.The

SDpart-throttleandclosed-throttleupshiftsanddownshiftsaresimilar

totheSBpart-throttleandclosed-throttleshifts.

SchedulesS1throughS4aretypicallyusedwithenginesusingvariablespeed

orall-speedgovernors.Thedifferencesbetweentheschedulesistypically

closetofullthrottle.SchedulesS5throughS8aredesignedtoprovidethe

Allison Transmission T 270 User Manual

Questions and Answers: