Service Manual

PTOClutchCircuit(continued)
ThePTORPMisdirectlyrelatedtoenginespeed.Agearboxlocatedbetween
theengineandthetandempiston(traction)pump(P1andP2)includesa1:0.42
gearreductionandahydraulicallyactuatedclutchforthePTO.
Thegearpumpsectionfurthestfromthepistonpump,gearpumpsection(P4),
suppliesuidtoavarietyofcircuitsincludingthePTOclutch.Hydraulicuidfrom
gearpump(P4)entersthemainmanifoldportPandowsthroughthesteering
priorityvalve(EC1);refertoSteeringCircuit(page5–18)forafullexplanationof
thesteeringpriorityvalve(EC1)operation.Fluidowcontinuesthroughtheow
regulatorvalve(EC2)whereitdeadheadsatsolenoidvalve(SP1).Fluidisalso
senttooneendoftheowregulatorvalve(EC2)spool.Aslongascircuitowis
blockedatsolenoidvalve(SP1),theowregulatorvalve(EC2)spoolisshifted
todirectowtothetractioncharge,2speeddrivemotorcontrol,brakerelease,
differentiallockandPTOclutchcircuits.
WhenthePTOswitchissettotheDISENGAGEposition,proportionalsolenoid
valve(EH)inthemainmanifoldisde-energizedandhydraulicowbypassesthe
PTOclutchcircuit.ReturnspringsonbothsidesofthePTOclutchassembly
keeptheclutchdisengagedandthePTObrakeengaged.Whenthemachineisin
AttachmentModeandthePTOswitchissettotheENGAGEposition,proportional
solenoidvalve(EH)energizesandhydraulicowisdirectedtoapistoninthe
PTOclutchassembly.HydraulicowpushesthepistonawayfromthePTO
braketoreleasethebrakeandtowardthePTOclutchtoengagetheclutch.
Note:Dependingontheprogrammableattachmentsettings,raisingand
loweringthehitchmayalsodisengageorengagethePTO.
Outcross9060
Page5–29
HydraulicSystem:HydraulicFlowDiagrams
18234SLRevC