Service Manual

TractionProblems
Problem
PossibleCauses
Themachineoperatesin1directiononly.
•Thesystemchargecheckvalveand/orthesystem
reliefvalveisnotfunctioning.
•Theoriceorscreeninthepiston(traction)
pumpcontrolassemblyisblockedordamaged.
•Thepilotdirectionvalvein4-wheeldrivecontrol
manifoldisdamagedordoesnotmovefreely.
•Thetraction-controlpotentiometerisnotfunctioning.
Thetractionpedalissluggish.
•Thetractioncontrolpedalisstuckordoesnotmovefreely.
•Thechargepressureislow.
•Thepistonpumpservocontrolvalveisdamaged.
Themachinetravelstoofarbeforeitstopswhen
youreleasethetractionpedal.
•Tractioncontrolpedalassemblydoesnotmove
freelyorisoutofadjustment.
•Thepistonpumpservocontrolvalveisdamaged.
•ThetractionpedaldoesnotreturntotheNEUTRALposition.
Thetractionpowerislostorthemachinedoesnot
operateineitherdirection.
•Thehydraulic-uidlevelinthereservoirislow.
•Thebrakesareappliedortheydonotmovefreely.
•Thechargepressureislow.
•Thepistonpumpbypassvalveisopenordamaged.
•Theoriceorscreeninthepiston(traction)
pumpcontrolassemblyisblockedordamaged.
•Thetraction-controlpotentiometerisdamaged
ordisconnected.
The4-wheeldrivedoesnotengage.
•Anelectricalproblemexists;refertotheChapter
5:ElectricalSystem(page5–1).
•Thesolenoidvalveonthe4-wheeldrivecontrol
manifoldisnotfunctioning.
•Cartridgevalvein4-wheeldrivecontrolmanifoldis
damagedordoesnotmovefreely.
The4-wheeldrivedoesnotdisengage.
•Anelectricalproblemexists;refertotheChapter
5:ElectricalSystem(page5–1).
•Thesolenoidvalveonthe4-wheeldrivecontrol
manifoldisnotfunctioning.
•Cartridgevalvein4-wheeldrivecontrolmanifoldis
damagedordoesnotmovefreely.
Groundsmaster5900TractionUnit
Page4–49
HydraulicSystem:Troubleshooting
08159SLRevC