Allison Transmission 4430 OFS

Thecontrolvalvemodulecontainsthefollowingcomponents:
•Variousvalvesandvalvebodiescontrollingandroutinghydraulic
pressuretotherestofthetransmission
•Rangeclutchandlockupclutchsolenoids
•Diagnosticvalve,valvebody,anddiagnosticpressureswitch
•Mainlterlifeindicatorvalve,valvebody,andlterlifepressureswitch
•Turbinespeedsensor(3000Seriesonly)
•Sumptemperaturesensor
10.6TRANSMISSIONSPEEDSENSORS
Threespeedsensorsareintegraltothetransmissionassembly.Thespeed
sensorsprovideinputspeed,converterturbinespeed,andtransmission
outputspeedsignalstotheTCM.Forthespeciclocationofspeedsensors,
refertoFigure2–1,Figure2–2fornon-PTOapplications.RefertoFigure2–3
andFigure2–5forPTOapplications.RefertoFigure2–6forthe4700/4800
transmissions.
Thetransmissioninputspeedsensorislocatedontheconverterhousing.The
transmissionoutputspeedsensorislocatedontheoutputhousing(exceptfor
the3700SPwhereitislocatedinsidethetransfercase).Bothspeedsensors
requireaconnectiontothewiringharness.
Themountingprovisionfortheturbinespeedsensordiffersbetweenthe
transmissionmodelfamilies:
•Fortransmissionmodelsinthe3000Series,theturbinespeedsensoris
internaltothetransmissionanddoesnotrequireanexternalconnection.
•Fortransmissionmodelsinthe4000Series,theturbinespeedsensor
isexternaltothetransmissionandrequiresaconnectiontothewiring
harness.
10.7TRANSFERCASE(DROPBOX)3700SPTRANSMISSION
(5THGENERATIONCONTROLSONLY)
Atransfercase(dropbox)moduleisprovidedfor3700SP-vehicleswhere
frontandrearwheeldriveisdesired.Thetransfercase(refertoFigure10–1)
ismergedwithasix-speedcloseratiogeartraintoproducea7-speed
conguration.OneofthetwoPowerTakeoff(PTO)driveprovisionsactuatea
scavengepumpforthetransfercase.Aremote-mountedcoolerisrequired
foradropboxunit.
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