VALVE GP-UNLOADING 1081170 - Caterpillar

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Operate the machine in each direction. Note the noises that are not normal and find the sources of the noises.Troubleshooting Problem List and Probable Causes
Problem 1The hydrostatic pump makes noise.Probable Cause
The hydraulic oil level is low.
The hydraulic oil is aerated.
The viscosity of the hydraulic oil is incorrect.
The charge pressure is too low.
The brakes are not fully disengaging.
The hydraulic inlet strainer may be clogged.
The gear pump or the piston pump are worn.
The hydraulic oil filter may be clogged.Problem 2The drive torque is not at specifications.Probable Cause
The crossover relief valve may be improperly set. Replace the crossover relief valve.
The crossover relief valve is stuck in the OPEN position. Replace the crossover relief valve.
The brakes are not fully disengaging.
The pilot pressure is too low.
The hydrostatic piston pump may not be functioning correctly.
The piston motor may not be functioning correctly.
The chain drives may be misadjusted.
The joystick controls may not be functioning properly.
The axle bearings may be damaged.Problem 3The output of the piston pump is low.Probable Cause
The hydraulic oil level is low.
The gear pump has excessive wear.
The pilot pressure is low.
The viscosity of the hydraulic oil is incorrect.
The speed sensing valve is out of adjustment.
The piston pumps have too much wear.
The crossover relief valves are