April 2017 Service and Repair ManualManifoldsPart No. 1272854 GTH-844 59How to Set the Differ enti al Loc k/J oysti c k System Press ureHow to Set the DifferentialLock/Joystick System PressureNote: Be sure that the hydraulic oil level is visible inthe inspection glass of the hydraulic tank.1 Install a 0 to 1000 psi / 0 to 100 bar pressuregauge into test port 'TP' at the top of theprimary function manifold, Refer to PrimaryFunction Manifold Components.2 Start the engine. Allow the engine to idle afterwarming the engine to operating temperature.3 Without operating any machine controls,observe the reading on the pressure gauge.Result: The pressure gauge reads 450 ±25 psi/ 31 ±1.7 bar. The pump is functioningcorrectly.Result: The pressure gauge fails to read 450±25 psi / 31 ±1.7 bar. The pressure settingneeds to be adjusted. Refer to RepairProcedure, How to Adjust the Function PumpPressure.4 Turn the machine off. Remove the pressuregauge from the test port.Bodily injury hazard. Sprayinghydraulic oil can penetrate andburn skin. Loosen hydraulicconnections very slowly to allowthe oil pressure to dissipategradually. Do not allow oil tosquirt or spray.5 Install a 0 to 1000 psi / 0 to 100 bar pressuregauge into test port 'TJ' at the top of thesecondary function manifold, Refer toSecondary Function Manifold Components.6 Start the engine. Allow the engine to idle.Result: The pressure gauge reads 400±20 psi/ 27.5 ±1.4 bar. The pressure setting is correct.Proceed to step 11.Result: The pressure gauge fails to read400±20 psi / 27.5 ±1.4 bar. The pressuresetting needs to be adjusted. Proceed to step7.7 Turn the machine off. Hold the differentiallock/joystick pressure reducing/relief valvewith a wrench and remove the cap (schematicitem PR1).8 Adjust the internal hex socket. Turn itclockwise to increase the pressure orcounterclockwise to decrease the pressure.Component damage hazard. Donot adjust the relief valvepressures higher thanspecifications.9 Install the relief valve cap.10 Repeat this procedure beginning with step 6.11 Turn the machine off. Remove the pressuregauge from the test port.Bodily injury hazard. Sprayinghydraulic oil can penetrate andburn skin. Loosen hydraulicconnections very slowly to allowthe oil pressure to dissipategradually. Do not allow oil tosquirt or spray.
