Chapter 6 Troubleshooting

Symptom and possible cause	Remedy
Vehicle is not able to travel when the engine is running
1.Speed is not selected. 2.Oil level in transmission is too low 3.The stem of transmission control valve is not reset 4.Transmission pump is damaged or the seal is worn	1.Select the speed and check the accuracy of speed selector. 2.Fill oil 3.Disassemble and inspect the valve stem, to find out the cause. 4.Replace oil pump or seal
Driving force is not enough
1.The pressure at the outlet of torque converter is too low. Pressure regulation for torque converter is failed. 2.Engine speed is too low 3.Clutch is spinning 4. Oil temperature in torque converter is too high	1.Check oil level in transmission. Clean the oil filters in oil pan and at the outlet 2.”Check the oil pressure and oil temperature of torque converter” to find out the cause of low engine speed. 3.Check the transmission oil pressure of clutch and the seals on piston 4.Vehicle should be stopped for cooling if the torque converter oil temperature exceeds 120°,
The pressure for speed change is too low
1. Malfunction of pressure reducing valve 2. Oil filter is blocked 3. Malfunction of oil pump 4. Serious leakage on seals of clutch	1. Find out the cause and solve the problem 2. Clean the filter 3. Replace oil pump 4. Replace seal
Torque converter oil temperature is too high
1.Oil level of transmission is too high or too low 2.Clutch is spinning	1.Fill oil according to requirement 2.Check clutch oil pressure
Steering torque is insufficient
1.The steering pump is worn and flow rate is insufficient 2.Safety valve pressure varies (priority valve) 3.Serious internal leakage in the steering gear	1.Check or replace the steering pump 2.Adjust its pressure (16Mpa) 3.Repair or replace

Symptom and possible cause	Remedy
Service brake force is not enough
1. Oil leakage in master cylinder or wheel cylinder 2. There is air in the brake hydraulic pipes 3. Pressure of compressed air is low 4. Rubber cup of booster is worn	1. Replace rubber cap or seal 2. Bleed the air 3. Check the airtightness in the air compressor, control valve and pipes 4. Replace the rubber cap
Gear cannot be put into position after service brake applied
1. The limit screw of air brake valve pedal is not properly set. Air brake valve cannot be fully reset. The gauge for pressure of speed change has no indication 2. Air brake valve piston is jammed, and the air is unable to return after brake is released 3. Brake valve stem is jammed	1. Re-adjust the limit screw of the pedal to make the air brake valve able to reset fully 2. Clean and check piston 3. Disassemble and check the brake valve stem
The power for lifting or tilting is insufficient
1. Safety valve is not properly set, system pressure is too low 2. Oil pipe and oil filter are blocked 3. Serious internal leakage in gear pump 4. Internal leakage in pipe or cylinder	1. Adjust system working pressure (16Mpa) 2. Clean and replace oil 3. Replace gear pump 4. Check the airtightness of the system by measuring the drift. The drift for new machine should be 10mm/15min
Pressure in air tank decreases rapidly after stopping
1. The inlet valve of air brake valve is clogged or damaged 2. Pipe connector is loosened or pipe is broken 3. The check valve for pressure controller is not airtight	1. Service is not needed if the decrease of pressure is less than 0.049MPa in 15-20 minutes. 2. Pump the brake pedal for several times to blow out the dirt by air. 3. The valve should be replaced if it is damaged. 4. Fasten the connector or replace the pipe 5. Find out the cause and make replacement as necessary
The reading in air pressure gauge is refreshed slowly
1. Pipe connector is loosened 2. Air compressor works abnormally 3. Oil drain plug of oil water separator is not screwed tightly 4. Malfunction of air brake valve	1. Fasten the connector 2. Check the condition of air compressor 3. Screw it tightly 4. Check and clean the interior