Service Manual

Afoursectiongearpumpiscoupledtothepiston(traction)pump.Thethirdgear
pumpsectionsupplieshydraulicowtothelift/lowercircuit,theenginecooling
fancircuitandthetractionchargecircuit.
Eachofthecuttingdecks(center,rightandleft)canbeloweredindependently
withtheuseofthree(3)switchesonthearmrestconsole.Pressingthefrontofa
liftswitchprovidesaninputfortheTECcontrollertoloweracuttingdeck.The
controllerprovideselectricaloutputstosolenoidsinthecombinationmanifoldto
allowappropriatemanifoldvalveshiftthatcausesacuttingdecktolower.
Areliefvalve(RV2)locatedinthecombinationmanifoldlimitslift/lowercircuit
pressureto110bar(1600PSI).Anadjustablepressurerelievingvalve(PR)
inthecombinationmanifoldmaintainsbackpressure(counterbalance)onthe
deckliftcylinderstoallowsomeofthecuttingdeckweighttobetransferredto
thetractionunittoimprovetraction.
Whenthelift/lowercircuitisnotbeingused(allliftswitchesintheneutral
position),solenoidvalveS1inthecombinationmanifoldisnotenergizedand
gearpumpsectionoilowisdirectedtowardtheenginecoolingfanmotor.
Note:Toloweracuttingdeck,theoperatormustbeintheoperatorseatandthe
tractionspeedmustbeintheLOWspeed(mow)position.
LowerCenterCuttingDeck
Tolowerthecentercuttingdeck,thefrontofthecenterconsoleliftswitchis
depressed.TheswitchsignalisaninputtotheTECcontrollerwhichprovidesan
electricaloutputtosolenoidvalveS6inthecombinationmanifold.Theenergized
solenoidvalveshiftstoallowapassageforoilowfromthebarrelendofthe
centerdeckliftcylinders.Theweightofthecuttingdeckcausesthecenterdeck
liftcylinderstoretractandlowerthecentercuttingdeck.CheckoriceOR5
(.070)underthemanifoldttinginportC2controlstheloweringspeedofthe
cuttingdeck.Oilfromtheretractingcylindersisdirectedtopressurereducing
valve(PR).Asreturnoilpressureincreases,thePRvalvewillshifttodirect
circuitoiltotheoillterandthentothetractionchargecircuit.
LowerRightCuttingDeck
Tolowertherightwingdeck,thefrontoftherightconsoleliftswitchispushed
asaninputtotheTECcontroller.Thecontrollerprovidesanelectricaloutputto
solenoidvalvesS1,S8andS9inthecombinationmanifold.Theenergized
solenoidvalvesshifttoallowapassageforcircuitoilowtotherodendofthe
rightdeckliftcylinder.ShiftedS1allowsgearpumpsectionoilowtobeavailable
forthelift/lowercircuits.ShiftedS8allowsanoilpathtotherodendoftheright
liftcylindertoretracttheliftcylinderandlowertherightcuttingdeck.Check
oriceOR7(.070)controlstheloweringspeedofthecuttingdeck.Oilfromthe
retractingcylinderisdirectedthroughenergizedS9,de−energizedS7andthen
topressurereducingvalve(PR).Asreturnoilpressureincreases,thePRvalve
willshifttodirectcircuitoiltotheoillterandthentothetractionchargecircuit.
Groundsmaster
®
4000-D&4010-D
Page5–21
HydraulicSystem:HydraulicFlowDiagrams
13202SLRevE