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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 Power Train Oil Pump
There is an indication of air in the oil
Probable 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.
Probable Cause
- Failure of the power train charging section of the transmission oil pump.
- There are bad 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.
Probable Cause
- The setting for the charging relief valve is too low. Add spacers.
- There are bad seals in a clutch of the transmission.
The oil pressure is too high
Probable Cause
- The setting for the charging relief valve is too high. Remove spacers.
There is a noise at the power train pump
Probable 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 pump failure.
Problem
Oil contamination
There is an indication of water in the oil
Probable Cause
- There is a failure of the power train oil cooler.
Problem
The Transmission Hydraulic System
Overheating
Probable Cause
- The oil cooler or oil cooler lines are restricted or blocked.
- Insufficient coolant flow or low coolant level.
- The oil level is too high.
- The torque converter has failed.
The machine begins to creep forward before the engine rpm achieves 1300 rpm.
Probable Cause
- The brake system
The drive shaft does not turn in NEUTRAL position.
Probable Cause
- The torque converter is damaged. Look for metal chips in the transmission magnetic screen.
- There is an improperly engaged transmission clutch.
When a shift is made to REVERSE or to any forward speed, the engine stops running.
Note: Be sure that the lockup clutch solenoid is disconnected.
Probable Cause
- The lockup clutch is stuck in the engaged position. Look for metal chips in the transmission magnetic screen.
The drive shaft turns in more speeds than NEUTRAL, but the wheels do not turn.
Probable Cause
- There is a slipping clutch. Look for debris from the clutches.
- The transmission clutch pressures are low.
The transmission will not stay in the selected speed position and Manual shifts are difficult in any direction (upshift or downshift).
Probable 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
The Transmission Hydraulic Control ( Primary Clutch Pressure)
The primary pressure is correct, but the maximum pressure is not correct.
Probable Cause
- The inner spring at the pressure control valve is weak or broken.
- The outer spring at the pressure control valve is weak or broken.
The pressure at one clutch is 0 kPa (0 psi).
Probable Cause
- The selector piston plug is not installed.
- The selector piston is stuck.
- The modulation reduction valve is stuck.
The primary pressures at all the clutches are 0 kPa (0 psi).
Probable Cause
- The probable cause is the pilot pressure.
The primary pressures at all the clutches are too low.
Probable Cause
- The probable cause is the power train charging section of the power train oil pump.
The primary pressure at one clutch is too low.
Probable Cause
- The selector piston is stuck.
- The inner spring at the pressure control valve is weak, broken or incorrect.
- The outer spring at the pressure control valve is weak, broken or incorrect.
- The primary pressure is set incorrectly. Add shims.
The primary pressure at one clutch is too high.
Probable Cause
- The inner spring is incorrect.
- The outer spring is incorrect.
- The primary pressure is set incorrectly. Remove shims.
A clutch has not disengaged when the next speed is selected.
Probable Cause
- The decay orifice is plugged.
- The drain orifice in the return end of the rotary selector spool is plugged.
- A selector piston is stuck.
- A load piston is stuck.
- A modulation reduction valve is stuck.
The pressure in one clutch at the high idle rpm is not correct, but the primary pressure in the same clutch is correct.
Probable Cause
- The wrong inner spring has been installed in the load piston.
- The wrong outer spring has been installed in the load piston.
- The inner spring in the load piston is weak or broken.
- The outer spring in the load piston is weak or broken.
- The load piston orifice is plugged.
The primary pressure in one clutch is not correct, but the pressure in the same clutch at the high idle rpm is correct.
Probable Cause
- The wrong inner spring has been installed in the load piston.
- The wrong outer spring has been installed in the load piston.
Problem
The Transmission Hydraulic Control (Clutch Pressures)
The pressures at all the clutches are 0 kPa (0 psi).
Probable Cause
- The probable cause is the pilot pressure.
The pressures at all the clutches are low.
Probable Cause
- The power train charging section of the transmission oil pump is bad.
- There is a restriction in the power train oil filter and/or other components.
- The relief valve in the transmission selector and pressure control valve is incorrectly set.
The pressure at any clutch is 0 kPa (0 psi).
Probable Cause
- The selector piston plug is not installed.
- The supply port of the rotary selector spool is plugged.
The pressure in a clutch does not increase above the primary pressure.
Probable Cause
- The load piston plug is not installed.
- The load piston orifice is plugged.
- There are broken springs in a modulation reduction valve.
The pressure in one clutch is not correct, but the primary pressure in the same clutch is correct.
Probable Cause
- There are broken springs in a modulation reduction valve.
- The wrong inner spring is installed.
- The wrong outer spring is installed.
- The wrong number of shims are installed.
The pressure in one clutch at the high idle rpm is correct, but the pressure in the same clutch at the low idle rpm is not correct.
Probable Cause
- There are bad seals in a clutch of the transmission.
The pressure in one clutch does not decrease rapidly or the low pressure remains in one clutch.
Probable Cause
- The decay orifice is plugged.
- The drain orifice in the return end of the rotary selector spool is plugged.
A clutch has not disengaged when the next speed is selected.
Probable Cause
- The decay orifice is plugged.
- The drain orifice in the return end of the rotary selector spool is plugged.
Problem
The Transmission Hydraulic Control (Pilot Pressure)
The pressure on the gauge is too low.
Probable Cause
- The setting of priority reduction valve is too high. Remove spacers.
The pressure on the gauge is correct, but the pressure at all of the clutches is 0 kPa (0 psi).
Probable Cause
- The operation of neutralizer valve is not correct. Disassemble the selector and pressure control valve. Check for any foreign material or for any parts that are damaged or worn. Be certain that the orifice and/or the ball check valve of the neutralizer valve are free of any debris.
- There is a restriction in the screen at the rotary selector spool.
- The pressure tap is not installed properly.
The pressure on the gauge is correct, but the pressure at all of the clutches is too low.
Probable Cause
- There is a restriction in the screen at the rotary selector spool.
Problem
Interaxle Differential
The solenoid for the interaxle differential has failed to energize
Probable Cause
- The solenoid for the interaxle differential is faulty.
- The floor switch has failed.
- There is a broken wire in the harness to the solenoid.
The pressure is not correct when the interaxle differential lock is engaged
Probable Cause
- The solenoid for the interaxle differential is faulty.
- Internal leakage
- The operating pressure is low.
Problem
Differential Lock
The solenoid for the differential lock has failed to energize
Probable Cause
- The solenoid for the differential lock is faulty.
- The floor switch has failed.
- The panel switch has failed.
- There is a broken wire in the harness to the solenoid.
Low oil pressure when the differential lock is engaged.
Probable Cause
- There is a fault in the control valve for the differential lock.
- There are bad seals in the clutch pack for the differential lock.
The differential locks are slipping
Probable Cause
- The clutch plates for the differential lock are worn.
- The pressure for the differential lock is too low.
- The accumulator for the differential lock is faulty.
Problem
Differential and Drive Axle
Metal particles attached to the final drive plug (filler and drain).
Probable Cause
- Mechanical failure of one or both final drives of that axle.
- There is a mechanical failure of components that are located inside the axle housing.
The oil level in the final drive (front or center) is too high and the oil level in the hoist and brake hydraulic tank is too low.
Probable Cause
- The brake cooling oil is leaking into the final drive. The inner Duo-Coneseal at the wheel brake has failed.
The oil level in the final drive is too low
Probable Cause
- The oil is leaking to the ground. Failure of the O-ring seal on the final drive housing.
- The oil is leaking to the ground. The outer Duo-Cone seal at the wheel brake has failed.