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Personal injury or death can result from sudden machine movement. Sudden movement of the machine or release of oil pressure can cause injury to persons on or near the machine. To help prevent possible injury or death, refer to the information in Testing and Adjusting, "Machine Preparation for Troubleshooting". |
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Problem
The Pump
There is a noise at the pump
Possible Cause
- There is air at the inlet side of the pump.
- There is debris in the system which is passing through the pump.
- The pump is cavitating.
- There has been a failure inside the pump.
Problem
The Transmission Hydraulic System
The hydraulic system is overheating
Possible Cause
- The oil cooler is restricted or blocked.
- The oil level is too high or too low.
- The pump is excessively worn.
- The torque converter has failed.
- One or more than one of the clutches in the transmission is slipping.
- The relief valve in the manifold of the control valve is not seated correctly.
- The filter for the transmission is partly blocked.
- The machine is being overloaded. The machine is being operated in a gear range that is too high for the load conditions. When this occurs the torque converter will slip excessively.
There is an indication of air in the oil
Possible Cause
- Check for oil leakage.
- There is air at the intake side of the pump.
The oil pressure is too low at low idle and the oil pressure is too low at high idle.
Possible Cause
- There is a failure of the pump.
- There are worn seals in a clutch of the transmission.
The oil pressure is too low at low idle and the oil pressure is correct at high idle.
Possible Cause
- The setting for the regulator valve (pressure) is too low. Replace the regulator valve.
- There are worn seals in a clutch of the transmission.
The oil pressure is too high
Possible Cause
- The setting for the regulator valve (pressure) is too high. Replace the regulator valve.
The drive shaft does not turn in the NEUTRAL position.
Possible Cause
- The torque converter is damaged. Look for metal chips in the transmission magnetic screen.
- There is an improperly engaged transmission clutch.
The transmission will not stay in the selected speed position and manual shifts are difficult in any direction (upshift or downshift).
Possible Cause
- The probable cause is solenoid leakage. A shift to a higher speed from the selected speed is an indication of a bad upshift solenoid. A shift to a lower speed from the selected speed is an indication of a bad downshift solenoid.
Problem
Transmission Performance
The transmission shifts slowly
Possible Cause
- Low oil pressure in the transmission hydraulic system.
- There is air at the intake side of the pump.
- Operation of the regulator valve (pressure) is incorrect.
- There is a restricted orifice in the modulating valves.
Low clutch pressures
Possible Cause
- The oil level is too low.
- The regulator valve (pressure) is worn.
- The pump is worn or there is a blockage in the transmission filter.
- The shaft of the clutch is worn or broken or the piston rings on the shaft of the clutch are worn or broken.
- The check valve for the piston at the respective clutch pack is sticking open.
The transmission does not operate in any speed, or the clutches slip in all speeds
Possible Cause
- The oil level is too low.
- There is a failure of the pump or failure of the drive to the pump.
- There is air at the intake side of the pump.
- Worn shift control, parking brake switch, neutralizer switch for the service brake, neutral start switch and associated wiring.
- The regulator valve (pressure) is worn.
- The relief valve in the manifold of the control valve is sticking open.
Pressure drop in forward and reverse
Possible Cause
- The regulator valve (pressure) is worn.
No drive in one direction, or in one speed
Possible Cause
- The forward/reverse direction clutch or a speed clutch is damaged or worn.
- There is an electrical problem. A component of the electrical control circuit or the wiring has failed.
- The modulating system is malfunctioning.