The performance checks can be used to find the probable cause of a known problem. Some problems may have more than one cause. These problems require specific testing to determine the actual cause.
One all wheel drive piston motor turns in the wrong direction.
- The locator pin in the distributor has been improperly positioned in the all wheel drive piston motor.
- The hoses may be crossed between the all wheel drive control valve and the all wheel drive piston motor.
Both all wheel drive piston motors turn in the wrong direction.
- The locator pins in the distributor have been improperly positioned in the all wheel drive piston motors.
- The hoses may be crossed on both sides between the all wheel drive control valve and the all wheel drive piston motor.
- The hoses may be crossed between the all wheel drive piston pump and the flushing and cooling control valve.
- The hoses may be crossed between the flushing and cooling control valve and the all wheel drive control valve.
The all wheel drive piston motor clacks during a sharp turn.
- The orifice plug in the all wheel drive control valve is missing.
- There may be blockage in the case drain line from the all wheel drive piston motors.
- The hydraulic oil pressure to the all wheel drive piston motors may be too low.
Only one all wheel drive piston motor turns when both all wheel drive piston motors should turn.
- The flow divider and combiner valve will not function correctly at low speed and at low pressure.
- The seal between the distribution valve internal block and the distribution valve external block is blown out.
- The orifice plug in the all wheel drive control valve is missing.
The seals in the wheel drives leak or the outer cover fails.
- An incorrect charge in the all wheel drive accumulator results in pressure spikes that are too high in the case drain lines of the all wheel drive piston motor.
- Case drain lines for the all wheel drive piston motors may be blocked.
- Improper assembly of the Duo-cone seal.
- Wheel bearings are loose.
- The hydraulic oil does not conform to the proper oil recommendation for the ambient operating temperature.
One all wheel drive motor or both all wheel drive motors click in fourth gear or in seventh gear.
- The cam ring is incorrectly oriented relative to the cover for the all wheel drive piston motor.
- The displacement signal is not getting to the all wheel drive piston motor.
- One all wheel drive piston motor or both of the all wheel drive piston motors have a failed displacement spool.
- One all wheel drive piston motor or both of the all wheel drive piston motors have a failed displacement spool.
- The all wheel drive electronic control module has failed .
When the machine is moving, the all wheel drive piston motors clack too much during engagement.
- The all wheel drive gear pump has failed.
- The orientation of the solenoid valves is not correct or the wiring to the solenoid valves in the all wheel drive control valve is not correct.
- The all wheel drive control valve has failed .
When the machine is moving, the all wheel drive piston motors clack too much during disengagement.
- When the drive spool is shifted to the freewheel position, the all wheel drive solenoid in the all wheel drive control valve is deactivated.
- The all wheel drive control valve has failed.
The all wheel drive piston motors will not engage.
- There is no power to the all wheel drive electronic control module.
- The all wheel drive electronic control module has failed.
- The all wheel drive control has failed .
- The all wheel drive solenoid has failed.
- The charge solenoid has failed.
- The transmission modulator switch has failed.
- There is no charge pressure or no flow.
- The drive spool and the charge spool are interchanged in the all wheel drive control valve.
The all wheel drive piston motors growl in low speed.
- The front wheel bearings have not been preloaded.
The all wheel drive control valve makes a noise at high system pressures.
- The crossover relief valve is not set correctly.
- The all wheel drive pressure sensor has failed .
The torque control lever has no effect on the pressure from the all wheel drive piston pump in forward speed or in reverse speed.
- The torque control lever is not sending the correct signal to the all wheel drive electronic control module.
- The all wheel drive piston pump has failed.
- The all wheel drive pressure sensor has failed.
- The crossover relief valve has failed.
The pressure from the all wheel drive piston pump will not increase.
- Low charge pressure.
- The proportional solenoid in the all wheel drive piston pump is not functioning.
- The torque control lever is not sending a signal to the all wheel drive electronic control module.
- The directional solenoid valve has failed.
- A spring in the flushing and cooling control valve has failed.
- The all wheel drive piston pump has failed.
- The all wheel drive pressure sensor has failed.
- The crossover relief valve has failed.
At high system pressures, the all wheel drive piston motors will clack while operating in fourth speed forward through seventh speed forward and third speed reverse through sixth speed reverse.
- The displacement spool has not shifted.
- The all wheel drive piston pump may be worn, resulting in excessive internal leakage.
- The cam rings in the wheel drives are incorrectly oriented.
- One all wheel drive piston motor or both of the all wheel drive piston motors have high leakage.
In fourth speed forward on hard pavement, the maximum pressure from the all wheel drive piston pump cannot be set to 34500 kPa (5000 psi) .
- The internal relief valves for the all wheel drive piston pump are not functioning correctly.
- Incorrectly adjusted forward flow and incorrectly adjusted reverse flow limits the all wheel drive piston pump.
- The high pressure relief valve in the all wheel drive control valve is set too low.
- The all wheel drive piston pump is worn, resulting in excessive internal leakage.
The all wheel drive system overheats too quickly at low operating pressures.
- The hydraulic oil temperature switch in the flushing and cooling control valve is not functioning correctly.
- The cooler bypass valve in the flushing and cooling control valve is not functioning correctly.
- The flow of hydraulic oil to the hydraulic oil cooler is obstructed.
- While the all wheel drive system is operating, the charge pressure is not correct.
- The all wheel drive piston pump is worn.
- The all wheel drive piston motor is leaking.
The all wheel drive piston motors growl in low speed.
- The front wheel bearings are not preloaded.