(1) Fault phenomenon
It shows that the engine throttle is fully open and the torque converter inlet oil pressure is less than the standard value under the zero speed condition of the forklift.
(2) Troubleshooting
First pull out the dipstick and check whether the torque converter oil level is between the two scribed lines. If the oil level is normal, check whether there is any leakage in the oil inlet and outlet pipelines. If there is any leakage, eliminate it according to the specific situation.
If the oil inlet and outlet pipes are well sealed, check the operation of the inlet and outlet pressure valves of the torque converter. If the pressure valve cannot be closed, the pressure valve shall be removed to check whether the components are worn, whether the oil circuit and oil hole are unblocked, and whether the spring has permanent deformation. When the wear of parts exceeds the limit value, they shall be replaced or repaired.
If the pressure valve works normally, the oil inlet pipe and filter screen shall be dismantled and inspected. If there is any blockage, the sediment shall be removed and cleaned. If the oil pipe is unblocked, the hydraulic pump shall be repaired and replaced if necessary.
3. oil leakage
(1) Fault phenomenon
It shows that there are obvious traces of oil leakage at the joint surface between the rear cover of the hydraulic torque converter and the pump wheel and the connection between the pump wheel and the hub.
(2) Troubleshooting
If there is oil leakage at the connection between the torque converter and the engine, a piece of white paper can be pasted at the process hole window. If oil is thrown from the connection after the engine is started, it may be that the bolts (or connecting rivets) at the pump wheel and the pump hub are loose, the seals are aging, the oil plug is loose or the gasket is damaged. At this time, tighten the bolts (or rivet the rivets) and check again whether there is oil leakage. If there is still oil leakage, replace the sealing ring.
If there is a large amount of oil leakage at the connection between the torque converter and the engine (oil channeling outward), it indicates that the pump wheel cover has cracks. Disassemble the torque converter and replace the pump wheel cover.
If the oil leakage position is at the oil filler or drain plug, check the tightness of the plug first. If the plug is too loose, retighten it; If the plug is not loose, check the threaded hole for cracks.
4. abnormal noise
(1) The fault phenomenon is that when the torque converter is working, there is a metal friction sound or impact sound inside.
(2) Fault diagnosis and troubleshooting first check whether the fixing bolts connecting the torque converter and the engine are reliable. If the fixing bolts are loose, tighten them and reach the specified torque; If the fixing bolts are tightened normally, drain some hydraulic oil from the torque converter to check whether there are impurities in the oil. If the oil is clean without metal powder, the bearing should be loose or worn; If the discharged oil contains aluminum fines, it indicates that the internal components are abnormally worn.
5. weak driving
(1) The fault phenomenon is that after starting in gear and increasing the engine speed, the forklift is weak and slow.
(2) For troubleshooting, first check whether the pressure indicated by the shift pressure gauge is within the normal range. If the pressure is too low, find out the influencing factors according to the second fault. If the pressure is normal and the driving is weak, the internal sealing ring of the torque converter may be damaged, the pump wheel may be worn or the turbine blade may be damaged.
Failure of the transmission friction clutch can also lead to poor driving. At this time, the end cover of the friction clutch can be removed to check whether the sealing ring is worn or aged and whether the end cover has grooves. It can be replaced or repaired as appropriate. If the friction clutch works normally, disassemble the torque converter and check the wear of the sealing ring, turbine and pump wheel.
After starting the engine, the vehicle cannot drive, or the valve element of the oil inlet and outlet pressure valve of the torque converter is stuck or the clutch cannot be engaged. Remove the oil inlet and outlet valves to check whether the valve core is stuck. If it is stuck, clean it to make it move freely. If necessary, replace the hydraulic oil; If the valve core is in good condition, the clutch may be "locked" and the gear cannot be engaged. Disassemble the clutch to eliminate the fault.
