VALVE GP-FLOW CONTROL 5I8746 - Caterpillar

Probable Causes
The viscosity of the oil is wrong.
The pump or the steering motor has failed.
The oil level is low.
The oil has been aerated, because a loose connection or restriction exists on the inlet side of either the steering charge pump or the implement pump.Recommended Actions
Note: Care must be taken in order to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting, and repair of the machine. You must be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component that contains fluid. Dispose of all fluids according to local regulations.The Viscosity Of The Oil Is Wrong.
Ensure that oil is the correct viscosity for the operating conditions. In order to determine the correct oil viscosity, refer to the Operation and Maintenance Manual, SEBU8408, "Lubricant Viscosities and Refill Capacities" for your machine.The Pump Or The Steering Motor Has Failed
Check the case drain flow rate for the steering motor. Damage to or excessive wear of the seal around the steering motor output shaft may allow hydraulic oil (case drain) to leak past the shaft seal. Since the steering motor is installed in a bore at the top, front of the main case, hydraulic oil (from the hydraulic system) that leaks past this seal will drain directly into the main case (bevel gear case). The main case is the oil reservoir for power train oil. This condition may cause the power train oil level to increase and at the same time cause the hydraulic oil level to decrease.Ensure that the steering motor is not worn to the point that the steering system cannot maintain the correct pressures. Wear to the steering motor rotating group may cause excessive internal (case drain) leakage. This condition may cause the steering motor to operate inefficiently, which results in wider (less sharp) turns, excessive noise while steering, low steering or charge pressures, and hesitation prior to turns.
Personal injury can result if the machine moves while testing.If the machine begins to move during test, reduce the engine speed immediately and engage the parking brake.
Start the engine and run the engine.ENSURE THAT THE SERVICE BRAKES ARE FULLY APPLIED THROUGHOUT THIS ENTIRE PROCEDURE.Warm the hydraulic oil to 65° 3°C (150° 5°F).
Stop the engine and disconnect hydraulic hose from the fitting on the manifold of the case drain for the steering motor.
Place the end of the hose in a suitable container with a known volume such as a 5 gallon bucket.
Install a plug at the fitting on the case drain manifold in the same place that the line for the case drain was attached to the steering motor.
Start the engine and set engine speed to HIGH IDLE (2200 rpm).
Move the steering lever to the full LEFT TURN position and hold it long enough to determine the case drain flow rate. Repeat this step in the full RIGHT TURN position.The motor's case drain flow rate in each direction should be approximately 4 L/min (1 gpm) in either direction.
If the motor's case drain flow